Pakistani lawyers, who often have been at the forefront of movements to unseat rulers here, are attempting to revive the protest effort against President Mohammed Zia ul-Haq's martial-law government by taking to the streets en masse.

Lawyers had already been participating in the campaign of the eight-party opposition alliance, the Movement for the Restoration of Democracy, gradually to fill the jails by offering anti-Zia activists for arrest.

At least 800 lawyers, some dressed in mourning and carrying copies of the suspended 1973 constitution, demonstrated in four major cities Saturday, Reuter reported. The largest rally was in Lahore, where more than 500 lawyers marched down a main street to the cheers of a large crowd. About 500 police, wearing helmets and steel-ribbed riot jackets, watched the peaceful march.

In Karachi, more than 100 lawyers squatted on a busy road for half an hour and offered funeral prayers for those who had died in the unrest. In both Rawalpindi and Peshawar, meetings of about 100 lawyers passed resolutions demanding an end to martial law. The protests closed most courts in the four cities.

"It is time for us to decide if we are going to do more than has already been done," said Hafez Lakho, president of the Karachi Bar Association in an interview. He said the opposition so far had demonstrated in a "most humble and peaceful manner," but conceded that other organizations were looking to the Bar Association for guidance before committing themselves to escalating the civil disobedience campaign.

Particularly in the dominant Punjab Province, labor unions, student organizations, merchants and other professional organizations have not joined the anti-Zia protest in full force, leading to a widespread perception that the opposition movement is losing steam and could evolve into little more than a continuing nationalist movement in Sind Province.

Lakho said the lawyers' marches would be peaceful but would inevitably result in mass arrests because congregations of more than four persons are banned under martial-law regulations.

"This foolish government is putting the challenge to us that this is not a popular uprising of the people but is a Sindhi nationalist movement confined to this province. He Zia is trying to create a rift between Sind and the Punjab for his own purpose," Lakho said.

Other members of the Karachi lawyers' community said that also at stake is the credibility of a profession that from the start of Zia's military rule six years ago has been in the vanguard demanding a return to democracy.

The lawyers seized the initiative after Zia dismantled much of Pakistan's judicial framework by suspending the Bill of Fundamental Rights, abolishing habeas corpus, extending civilian jurisdiction to military courts and firing 19 Supreme Court and provincial high court judges.

Karachi lawyers turned out last Tuesday in large numbers in front of the District and Sessions Courts here when Begum Gulzar Shibli, president of the Progressive Workers' Union of the Karachi Steel Mill appeared with an opposition party leader to court arrest.

Shibli, the first woman to ceremoniously surrender to police here since five women opposition activists were arrested on Aug. 1, arrived before a large but peaceful crowd and unfurled an anti-Zia banner--the signal for police intervention in the fill-the-jails campaign. With her was Hassan Feroz, head of the banned National Democratic Party.

As police tried to seize Shibli, lawyers formed a cordon around her and took her inside the fenced court compound. Held aloft on the shoulders of the lawyers, Shibli, 28, shouted, "To call Zia a dog is to insult the dog!" She then surrendered to police in the street and was driven away in a van.

Absent from the crowd were the pro-Zia supporters who the day before--in the tough Liaquatabad district of North Karachi--assaulted foreign journalists. Twenty-eight persons were injured, two seriously, by a hand grenade thrown in the police compound.

Lakho rejected compromise on the demand that the suspended 1973 constitution be restored. It has been suggested that if Zia agreed to reinstate it, it would exclude an article that provides for the execution of anyone convicted of forcibly overthrowing the government and abrogating the constitution.

Lakho said neither Zia nor anybody has the right to amend the provision in the constitution's Article 6 but that any successor government would probably show some leniency and commute a death sentence for sedition to imprisonment, as happened when the military government was ousted in Greece.

When asked how he expected Zia to reinstate a constitutional provision that could lead to his own hanging, Lakho replied, "This nation is a grateful nation and would forgive his barbarism and save his neck to save Pakistan from further bloodshed."

Other opposition leaders have also said the Article 6 provision is not negotiable, giving rise to speculation that such a public posture alone will discourage Zia from opening a dialogue with the Movement for Restoration of Democracy.