After six years of military rule, Pakistan may be on the verge of receiving a revamped political system. President Zia ul-Haq has promised to disclose on Friday (Aug. 12) his blueprint for a government, which may include relaxation of his regime of mixed martial law and civilian rule. Some newspapers and analysts say his Friday speech - coming two days before the 36th anniversary of the country's independence from British rule and separation from India - may lead to a referendum on Pakistan's political direction.
In preparing for the declaration, the country's outlawed political parties are planning a mass movement of ''civil disobedience'' and electoral campaigning. Many fear this could set the stage for another outburst of the civil strife and political repression that have beset this country in the past.
As part of the national buildup to the announcement, Zia has received recommendations from special groups, including the Majlis-i-Shoora (the Federal Advisory Council appointed to take the place of an elected parliament) and an Islamic panel which consulted with Saudi Arabian scholars.
Zia, despite a resurgence of the political agitation that has led to postponement of a return to civilian rule in the past, has vowed he would stick to the target date he set. But he also warned that there was no point in holding elections just for the sake of elections. He added, however, that there was no alternative to elections in the Islamic system he has been introducing.
General Zia, the former chief of Pakistan's armed forces, led a military putsch that overthrew the left-wing elected government of Zulfikar Ali Bhutto in July 1977. Mr. Bhutto was later hanged, despite worldwide appeals for clemency, for his alleged link with the murder of a political opponent.
With the backing of fundamentalist Muslim parties and the military, Zia has led the country longer than any other post-independence leader and has established strong pro-Western ties while keeping good relations with the Soviet Union.
Under the martial law that has existed under Zia, few persons share their political opinions or forecasts. A Cabinet member speaking privately in Islamabad recently would say only that Zia's declaration Friday would mark a ''watershed'' for the country. He added that Zia was ''keeping his cards very close to his vest'' up to the last minute.
Most of the special advisory bodies and political parties still functioning despite their official banning during martial law have advocated a restoration of the suspended 1973 constitution and the staging of national partisan elections. In 1981 nine such political groupings formed a loose and fragmented coalition known as the Movement for the Restoration of Democracy (MRD). Notable exceptions to these calls for elections have been powerful fundamentalist Islamic forces and an advisory council on Islamic ideology.
A foretaste of what could take place after the August announcement occurred July 5, the sixth anniversary of Zia's military overthrow of former President Bhutto. The MRD called out its forces in most major cities in a ''black day'' demonstration that resulted in numerous arrests and clashes with police.
Mr. Bhutto's Pakistan's People's Party, regarded as the most popular vote-getting organization, is also banking on nationwide nonpolitical elections to local councils next month as a referendum on the Zia regime and a test of its strength. But many other parties want to boycott the September elections - in which party participation is strictly prohibited - as undemocratic. Some fear the candidates associated with the Pakistan's Peoples' Party will walk away with the elections, as it has in earlier local voting.
In the past Zia has adroitly dealt with any opposition with a mixture of what a Pakistani source calls ''intelligent dictatorship'' and selective repression. Bhutto's daughter, a potential heir to her father's party leadership, has been under house arrest for years.
Another top opposition leader was also put in the curious legal position of being banned from every province in the country, an interdiction he is contesting in the courts. Yet some limited political criticism is tolerated.
The Zia regime has benefited from economic prosperity in a country that still registers a $350 annual per capita income. ''Economically, we've probably been the luckiest country on earth in the last five years,'' noted the editor of the leading economic magazine in Karachi recently. This stems mostly from an increase in food production and exports and from income earned by 3 million Pakistanis working abroad.
The government has received large-scale American military and economic assistance to cope with the presence of Soviet troops on its border in neighboring Afghanistan and to deal with the influx of nearly 3 million Afghan refugees across this border.
But the internal social and economic pressure arising from the presence of the millions of Afghan refugees may be, in the eyes of some informed sources, the biggest challenge to the Zia regime. A combination of domestic and foreign policy problems could lead to the downfall of the president in the coming months , in the eyes of some analysts.
That's why Zia's future may depend on how he handles his Friday announcement and the subsequent civil disobedience campaign by the opposition. The leading Lahore English-language daily newspaper, the Muslim, recently characterized the forthcoming development as ''President Zia ul-Haq's single most important political initiative since the hanging of Mr. Bhutto four years ago.''