The death of President Mohammed Zia ul-Haq offers a unique chance for this Moslem country near the Soviet bloc to create a broad-based democracy.

Western diplomats and Pakistani political observers, speaking on condition of anonymity, said it was too early to say precisely how the army general's death would affect the turbulent political scene in the nation of 107 million.Pakistani politicians disagree with foreign observers who say the country was left without a leader. Zia and his military chiefs died Wednesday when their C-130 transport plane exploded and crashed in eastern Pakistan.

"There is no leadership crisis. The question is how we put the system back in shape," said Mohammad Khan Junejo, head of the opposition Pakistan Moslem League and prime minister until Zia fired him and dissolved the National Assembly on May 29.

Zia ruled under martial law from 1977 until December 1985.

Ghulam Ishaq Khan, 73, who automatically took over as acting president after Zia's death, "is not as clever as Zia, but he is a broad-based, experienced technocrat who is acceptable to even the most outspoken members of the opposition," said a Pakistani political observer.

Ishaq Khan was a former defense minister, "so he is not inimical to the army either," the observer said. "The equation is good, and Ishaq Khan might be neutral and acceptable enough to remain in the job if he decides to run" in elections set for the fall.

The army is the nation's most powerful constituency, and any new government will need its seal of approval to rule.

Zia, who was army chief of staff when he took power in a bloodless military coup in 1977, made sure no officers were waiting in the wings to do the same and the military was largely depoliticized, obervers said.

"I don't think military rule is in the cards here," said a Western diplomat. "This army is British- and American-trained and is not an army like those in Latin America. They have acted responsibly so far."

"It could also be a golden opportunity for opposition parties to take some power and open up the political system," the diplomat said. Pakistan has only had two free elections since the end of British colonial rule in 1947.

But the person who stands to gain most from Zia's death is Benazir Bhutto, leader of the Pakistan People's Party, the country's largest opposition group. She is the daughter of Zulfikar Ali Bhutto, whom Zia overthrew and executed in the late 1970s.

She reacted to Zia's death by saying, "Life and death is in the hands of God." Ishaq Khan's announcement that parliamentary elections would be held Nov. 16, as planned, was "a positive development," she said.

Whoever takes over will have a full plate of domestic problems.

For the past five years, violence has grown between rival ethnic groups such as the Pathans and the Mohajirs. Disputes also have erupted between Sunni Moslems, who account for about 92 percent of the population, and Shiite Moslems, 5 percent of the people.

The new leadership also will have to woo the influential religious community, although Zia's policy of Islamization is likely to be scaled down. A deeply religious man, Zia decreed in June that Islamic law would take precedence over all other law. But observers said there was little overt support for such a policy.

Other domestic troubles include the flowering of an underground government run by heroin barons and their armed gangs.

The new leader will also face a harsh economic challenge.