A six-member commission including a French jurist and representatives from Algeria and Bangladesh is expected to gather here early next week to prepare for the Iran fact-finding mission that is the trigger for the release of the American hostages in Tehran.

Although the names of the commission members were being kept secret today, diplomatic sources in New York said they include Louis Pettitti of France, a judge of the European Court of Human Rights, and Mohamed Bedjaoui, he Algerian ambassador to the United Nations.

U.N. Secretary General Kurt Waldheim is expected to announce the commission's membership in the next day or two. A U.N. spokesman said tonight that the announcement, initially expected today, had been held up while the "nuts and bolts" of the commission's mandate are worked out.

Diplomatic sources in Washington and New York said the mandate would be limited to gathering facts without ascribing blame for the 14-week U.S.-Iran confrontation.

The sources said the mandate, as worked out by Waldheim, has the approval of the U.S. government, which had insisted that the commission's inquiries into Iranian complaints against the deposed shah, Mohammad Reza Pahlavi, be restricted to gathering facts and making them public without moral judgments.

As a result, the sources added, the United States is expected to follow the public announcement of the commission's members and mandate with a statement that it agrees to the arrangement.

U.N. sources said the commission also is expected to include representatives from Bangladesh and Syria, and Andres Aguilar of Venezuela who recently resigned as president of the Interamerican Human Rights Commission. He now heads Venezuela's delegation to the International Law of the Sea Conference.

Reached at his home in Caracas, Aguilar said he could not comment on the Iran commission.

U.N. spokesman Rudolf Stajduhar said the full list would be announced after Waldheim clarifies "some aspects" of his delicate negotiations by long-distance telephone with officials in Washington and Tehran.

According to reliable sources, the main delay involves formal notification to Waldheim of some nominees' willingness to serve on the commission and, in the case of some who are government officials approval from their governments.

Another delay arose when both the United States and Iran resisted the appointment of former Irish foreign minister Sean MacBride because of his alleged sympathies for the Soviet Union.

Despite the last-minute hitches, quick formation of the commission is considered virtually certain. Although Stajduhar declined to say whether a specific timetable had been established for linking its work to release of the hostages, Washington sources said a time span of roughly two weeks is involved.

That, the sources explained, means that the commission's mandate is expected to state that it has two weeks to complete its work in Iran and that the hostages' departure from Iranian soil would be timed to coincide with the commission's publication of its findings.

Some sources have said the plan calls for putting the hostages in the custody of a third party, such as the International Red Cross, in the interim. However, that was disputed by other sources today, so it is unclear who will have charge of the hostages while the commission is at work.

Reliable sources in Washington said, though, that the United States is working on the assumption that Iran has accepted the principle of a straight and direct trade-off -- that the naming of a commission and the completion of its work means that the hostages will be freed at the end of the process.

The sources said this point has been obscured by conflicting statements from officials in Iran and by speculation in several places that other factors might be involved in the deal.

The statements and speculation have involved such matters as Iran's demand that the United States free the approximately $6 billion in Iranian assets frozen in U.S. banks, Iranian President Abol Hassan Bani-Sadr's call for U.S. "self criticism" about its activities in Iran, and Iranian pursuit of attempts to extradite the shah from Panama.

However, the sources said, negotiations on these issues are taking place separately from the commission-for-hostages deal being worked out through Waldheim's intermediary offices, and are not a precondition for progress on that arrangement.

Instead, the sources added, these so-called "side matters" are largely being covered by a separate U.S.-Iran agreement in principle to attempt to restore some semblance of normal relations between the two countries.

Similarly, the sources said, the question of extraditing the deposed shah is being treated in Washington as a matter between Iran and Panama. The expectation is that Iran will go through the motions of asking for the shah's extradition but tht Panama will reject it on legal grounds.

Some Washington sources, citing the volatility of Iran's internal situation and the many unpredictable turns the crisis has taken in 14 weeks, said unexpected hitches and delays could interfere with the scenario taking shape at the United Nations. But, the sources added, as of tonight, arrangements seemed to be proceeding on track toward putting the commission in Iran in the near future and releasing the hostages roughly two weeks later.