A Pakistani youth who was sentenced last summer to have his right hand amputated for stealing a clock from a mosque is still sitting in prison while Islamic scholars debate whether just the fingers or the whole hand should be severed and whether the amputated limb then becomes the property of the state or the thief.

A Karachi bus driver who in 1981 was sentenced to be stoned to death for adultery is still awaiting a review of the piousness of the required four witnesses before the sentence can be executed.

An intense debate is continuing over whether qisas -- "eye for eye" retaliation -- should be imposed for injurious assault and murder, or whether "blood money" compensation should be paid. That debate rages even though the federal shariat, or Islamic law, court ruled in 1979 in favor of compensation, partly because it would be impossible to duplicate some injuries exactly.

As the martial-law government of President Mohammed Zia ul-Haq, who begins an eight-day visit to the United States this week, continues to transform Pakistan into a fervently Islamic fundamentalist state, controversy surrounds the speed and methodology of the process, although the debate tends to simmer out of public view.

Zia left Sunday for Washington, where he is expected to meet with President Reagan and other U.S. officials, Reuter reported. Pakistani officials said there was no fixed agenda for the visit but discussions would include issues such as U.S. aid to Pakistan, the Soviet intervention in Afghanistan and the situation in the Middle East.

The Associated Press reported that the government released five prominent political opponents Sunday, and diplomatic sources said that Zia wanted to avoid the embarrassment of being questioned in Washington about his human-rights record.

The five, among more than a dozen in political detention since a crackdown last week, included Mumtaz Ali Bhutto, a former communications minister, cousin of former prime minister Zulfiqar Ali Bhutto and a leader of Bhutto's Pakistan People's Party. Also released, according to AP, were Ghulam Mustafe Jatoi of the Sind People's Party and Meraj Mohammed Khan, secretary general of the Movement for the Restoration of Democracy, a coalition demanding an end to martial law.

Statistics on hudood sentences -- those imposed under strict Islamic practices -- are hard to come by in Pakistan. But Amnesty International earlier this year reported that 22 convicted thieves have been sentenced to amputation since Zia came to power, and none of them has had the sentence executed. There also have been no stonings. Compounding the amputation controversy has been a refusal by physicians to perform the operation.

The issue is important, however, because Zia has said that martial law cannot be replaced by democratic elections before the completion of a restructuring of the social order and the jurisprudence to conform with Islamic values dictated in the Koran.

Unlike in Iran, where the laws and social order were transformed almost overnight following the 1979 revolution, the process of Islamization in Pakistan has been fitful at times and always laborious, moving at a pace that government officials say is designed to avoid mistakes made in haste while producing a model of religious order for the entire Islamic world to follow.

"If we wanted to change the system in accordance with the 2nd century, we could do it in one sentence. But we are proceeding with caution and thoroughness," Aftab Hussain, chief justice of the federal shariat court, said in an interview.

I.A. Imtiazi, secretary of the Ministry of Religious Affairs, said, "In the West, they think that Islamization means stoning and flogging fornicators. But Islam is an attitude to life that affects all words and deeds. A new look is being taken at every aspect of life in Pakistan to get rid of anti-Islamic aspects. We are taking small, careful steps, but the objective is clear."

Since Zia seized power five years ago and had Bhutto hanged, Pakistan has made significant progress in some aspects of Islamization apart from the harsh laws prescribed in the Moslem holy book, the Koran, and its supplement, the Sunna.

The effort has been driven by a resolve born out of the very creation of Pakistan 35 years ago as a predominantly Moslem country in contrast with neighboring India, which is predominantly Hindu. After foundering in inertia through successive secular governments, the Islamization drive was rekindled by Zia.

Hundreds of new mosques and religious schools have been built; the practice of fasting and making pilgrimages to Mecca has been revived; strictures against intoxicants and un-Islamic dress and entertainment have been tightened; tentative steps aimed at eliminating, or at least reducing, the charging of loan interest have been taken, and an ambitious compulsory tithing program has been started.

A special social reform committee has proposed, and Zia's advisory council is studying, a wide range of Draconian new laws, including: death for drug trafficking and prostitution, watchdog committees to safeguard public morals, measures to discourage women from buying jewelry and highly embroidered clothes, a ban on ballroom dancing and "storm action" against obscene literature, in which offensive books would be burned in bonfires.

Yet some current laws and traditions do not fit this mold. The rules of evidence for hudood offenses are so stringent that in most cases a confession is required, and even then, if a confession is retracted, the punishment cannot be applied.

In the case of sexual relations out of wedlock, four witnesses to the actual act of coitus are required, and they must be proved to be pious witnesses. "This is not punishment for adultery. This is punishment for doing it in public," Hussain commented.

But from both poles of the religious spectrum in Pakistan, there has been criticism of the pace of Islamization, albeit subdued and cautious, given the authoritarian nature of the martial-law government.

Zia's government has been accused both of moving too fast and too slowly, of having too fervent an outlook on Islam and of being too fuzzy in its perspective on the new religious order.

Overt secular opposition appears to be minimal, partly because of the propitiousness of discretion, but also because most Pakistani Moslems feel strongly about their religion.

Even secular Pakistanis who have no qualms about serving liquor to Western visitors in their homes or making disparaging jokes about "mad mullahs" of the ulema, or traditionalists, often get touchy when non-Moslems initiate such humor.

But there is incipient secular opposition to Islamic reform, surfacing occasionally in the form of letters to the editors or in petitions submitted to the court challenging changes of laws.

"Most of us have our own views on what Islam is," Imtiazi said. "An unorthodox person may think all women should be behind veils and in the kitchen making cookies. That's not my perception of Islam. I believe women have a role, and that it should not necessarily be in subordination to the male."

When asked how that view -- and Zia's repeated assertions that women have a role in national progress -- squares with the government's refusal to let women compete in the recent Asian Games in New Delhi, Imtiazi said, "It's a question of methodology. Suppose the government digs in its heels and says women are going to the games. Will it damage Islamization? Is it worth it? We have more important things to think about."

More intense views on the pace of Islamization than those expressed by secular opponents, however, come from the traditionalists and fundamentalists, most noticeably from the three judges representing the ulema on the shariat court and the traditionalists appointed to the Council of Islamic Ideology, which has been empowered to make the law and social order in Pakistan conform to Islamic values.

For example, when controversy arose in 1980 over stoning, which is not prescribed in the Koran, the shariat court ruled that the practice was not an Islamic punishment. Three traditionalists were added to the court, which must uphold all sentences under the hudood laws on theft and sexual crimes, and the court then ruled that stoning is an Islamic punishment.

The fundamentalist Jamaat Islami Party on occasion has complained that the Islamization process is being implemented too slowly.

A Pakistani fundamentalist scholar who taught in Tehran for five years and returned last year complained that land reform along Koranic lines was not being implemented fast enough, saying, "It is a difference between rebuilding an entire structure and whitewashing the outer walls. In Pakistan they whitewash the walls. In Iran it was a reconstruction effort."

Corporal punishment under hudood, which in Arabic means the limit, is reserved for offenses felt to be especially repugnant to Islam, such as adultery, fornication and thievery.

Harry Minges, an Islamic scholar with the Christian study center in Rawalpindi, said the tendency in Islam is not to impose hudood punishments, because they are regarded as God's punishment and mortals may make a mistake in the process.

"The tradition was never strong on implementing it, but its value is seen as a deterrent. If you can come up with an excuse for not implementing it, all the better," Minges said.

Flogging, however, has been carried out widely in Pakistan. Amnesty International reported that 155 criminals were sentenced in 1980 to be flogged and that 193 political prisoners have been sentenced to be flogged since 1977.

Last week it was reported in Pakistan that at least four women were flogged in the past several months in Peshawar, in the Northwest Frontier Province, for having sexual relations out of wedlock.

Under a February 1979 amendment to the whipping laws, "minimal force" is supposed to be used in floggings, with the lasher supposedly not being allowed to run up to the defendant or raise the cane above his head. However, eyewitnesses to an April 1979 mass public flogging at Rawalpindi airport said that maximum force was used.

Buffeted by criticism from both secular moderates and impatient fundamentalists, Pakistani officials say the process of Islamization of Pakistani society is a gradual evolutionary one whose conclusiion is inevitable, given the reason for Pakistan's existence.

We have taken some steps which not long ago would be thought impossible. We are on a course from which we will not turn back, no matter what people in the West think," Imtiazi said.