Saudi Arabia and the United Arab Emirates have offered to guarantee any settlement worked out between Prime Minister Zufiqar Ali Bhutto and his political opponents whose violent demands for his resignation have crippled much of Pakistan for the last seven weeks, an opposition leader announced tonight.

Pir Sahib Pagaro, acting president of the opposition Pakistan national Alliance, told reporters that he is "not confident" that a compromise could be worked out, however. He also cautioned that Alliance leaders do not believe that Bhutto would abide by any agreement.

He added that plans for a protest march Saturday on Bhutto's official residence in nearby Rawalpindi are continuing.

"Our Arab brothers will see that Mr. Bhutto will not stand by any commitments he makes to us," the Pir said. "I'm certain that whatever is decided Mr. Bhutto will not honor it, despite the Arab guarantors."

The two oil-rich Arab states have powerful leverage on Pakistan. Both have granted this improverished country an open the line of credit, and Saudi Arabia is the leading donor of economic aid without which Pakistan could not survive.

The government, which has armed itself with special powers, has banned all processions and public gatherings in the two cities for a week. Anyone caught violating the ban is subject to be shot on sight.

Under another ban, all land traffic into Islamabad and Rawalpindi has been halteduntil Saturday night. Opposition spokesmen say that "thousands" of would-be demonstrators have already been arrested. Other thousands have managed to slip Rawalpindi, however, and will go ahead with the march, an Alliance official said.

The Pir, who considered a saint by a small group of Pakistani Moslem known as Hurs, told journalists that he had met today with other leaders of the nine-party Alliance at the police guesthouse outside Rawalpindi where they are detained.

Suweidi met separately with opposition leaders and Bhutto and offered his government's good offices as a guarantor of any settlement, the Pir said. Yesterday, he said, Saudi-Arabia made a similar offer.

The Pir said the Alliance had not requested intervention by the Arabs but was willing to accept their offer.

The Pir called Bhutto the "mad chairman" of the ruling Pakistan People's Party. The opposition does not recognize Bhutto as prime minister, saying the March 7 elections that returned him to power were rigged.

Saturday's procession is to wind through seven miles of Rawalpindi's congested old bazaars and slum neighborhood.

[In Washington, Under Secretary of State Philip Habib protested at the Pakistani embassy yesterday a Bhutto speech Thursday accusing the United States of backing the opposition in an attempt to overthrow him.]