The government of President Suharto is expanding a crackdown on dissidents, charging a former Cabinet minister with plotting to assassinate the president and establish an Islamic state.

Currently on trial in Jakarta for the alleged plot is Mohammed Sanusi, 65, light industries minister from 1966 to 1968 and now a leader of a moderate Islamic organization.

Four Moslem militants also are being tried separately in the eastern Java city of Malang for participation in the alleged plot and involvement in a series of bombings between December 1984 and March 1985. Blasts at a Roman Catholic church and the Borobudur Buddhist temple caused no casualties, but the bombing of a tourist bus killed seven persons.

[On Saturday, prosecutors demanded the death penalty for one of the four Malang defendants, Mochamad Achwan, 37, a shoe repairman, who is accused of buying explosives for the bombings and of conspiring to overthrow Suharto, Reuter reported.]

Sanusi is among the most prominent of dozens of dissidents who have been charged with subversion and related offenses in at least 35 trials since a September 1984 riot in Jakarta's port district slum of Tanjung Priok. At least 30 persons were killed when troops opened fire on Moslem protesters, the military has said, but dissidents put the death toll at more than 100.

A few days later, a group of dissidents including 16 members of the Petition of 50, a moderate opposition group, issued a white paper challenging the government's version of the incident. The following month, bombs exploded at two branches of the Bank Central Asia, an institution owned by a Chinese financier and friend of Suharto, Liem Sioe Liong. Two persons were killed and several injured in the blasts.

Government prosecutors have sought to link Sanusi and other reputedly moderate dissidents to the bank bombings and similar acts of violence. In May 1985, Sanusi was sentenced to 19 years in prison for allegedly financing the bank bombings. Five Moslem militants were convicted of having carried out those attacks. In January, a retired Army general and former secretary general of the Association of Southeast Asian Nations, Hartono Rekso Dharsono, 60, was sentenced to 10 years in prison for allegedly inciting Moslems to rebel against the government.

At least seven Moslem clergymen also have been sentenced to jail terms, including a wheelchair-bound 72-year-old professor at a Jakarta Islamic college. The professor, Usman Hamidy, received an eight-year prison sentence recently on subversion charges in connection with the Tanjung Priok incident.

Indonesia is the world's largest Moslem country, with about 90 percent of the population of 163 million professing adherence to the faith. The Suharto government has insisted, however, that all political parties and other mass organizations adopt the five-point state ideology, called Pancasila, which stresses belief in one God without reference to a specific faith.

Dissidents charge that the continuing crackdown is at least partly related to general elections scheduled for next year.

"It's almost a standard pattern every time a general election comes nearer," said Slamet Bratanata, a former minister of mines and a member of the Petition of 50 group. He said the government wanted to ensure its control over the election and head off any agitation by militant Moslems, even though all political parties are dominated by the government and candidates for the legislature must be cleared by the state security apparatus.

Bratanata described the ruling Golkar (Functional Groups) party as "an arm of the military" and the two nominal opposition parties, the Indonesian Democratic Party and the Moslem United Development Party, as Golkar's "concubines."

In a three-day congress this month opened by Suharto, the Indonesian Democratic Party was unable to choose a new leader because of factional bickering. As a result, the government stepped in and dismissed the present leadership, saying the home affairs minister would make the choice.

"The three parties are all subject to some degree of central guidance," said a senior western diplomat. "This is not a society that tolerates dissent in any significant degree."

In his current trial, Sanusi was accused of having hatched plots on three occasions in 1982 and 1983 to assassinate Suharto by blowing up his car, bombing the legislature and attacking him at the Borobudur temple. The prosecution presented witnesses who claimed Sanusi discussed the plans with them and spent more than $6,000 on the plots. But the witnesses said no attempts were made to carry them out.

"I don't understand the indictment," Sanusi told the court April 15. "It is illogical." He denied all the charges in what he called "an extraordinary, supersensational indictment, which is based on slander." Sanusi also charged that the testimony against him came from witnesses who had been tortured.

The charges against Sanusi appear to have met with widespread disbelief in the Indonesian capital. Crowds of Moslems have turned out at his court appearances to express their support, often shouting "God is great" in Arabic.

"I don't believe in that plot," said Mudjito, 47, a resident of a Jakarta squatter settlement. "Sanusi and the others, they are the true Moslems."

"It's too fantastic," said Adnan Buyung Nasution, a dissident lawyer who defended Dharsono. "It's ridiculous."

Nasution himself is now a target in the crackdown, with the government seeking to disbar him for an outburst when a military officer intervened to silence the audience at Dharsono's trial. Nasution has argued that there is no legal basis for the disbarment move because no law or regulation exists governing disciplinary proceedings for lawyers.

The International Commission of Jurists has taken up the case, which it described in a statement this month as "a strongly political one." It urged Indonesian authorities not to decide the case until proper procedures for disciplinary hearings are established and the matter is reconsidered under such proceedings.