Iran took another step today on its tortuous road toward the establishment of a parliamentary government that will be responsible for determining the fate of the American hostages.

The Majlis (parliament) elected six lawyers as members of the 12-man Council of Guardians, which is empowered to judge whether the laws passed by the legislature are in accordance with Islam and the constitution. The other six members, all clergymen, were appointed last February by the country's religious leader, Ayatollah Ruhollah Khomeini.

The completion of the council means that when the Majlis meets again Sunday it will be capable of passing legislation. Its first action is scheduled to be approval of a prime minister and Cabinet. No firm date has been set for President Abol Hassan Bani-Sadr to present his choice to parliament, but it is expected to be within the next week.

The president said in a television interview today that it was "very likely" that a decision on the hostages would be made by the Majlis "in the next few weeks."

Many such deadlines, vague or specific, have slipped by during the hostages' 257 days of captivity. Few observers will be surprised if the Majlis takes longer than a few weeks to make a decision or, more likely, turns the issue back to the government, even though Khomeini has left the decision to parliament.

A close aide to Bani-Sadr recently outlined a scenario in which the Majlis would approve a bill laying out general guidelines and order the new government to negotiate with the United States. In this official's optimistic view, the guidelines would not include a demand for the return of the ousted shah, Mohammad Reza Pahlavi -- the original reason for the seizure of the American Embassy Nov. 4.

Instead, after a short debate, parliament would call for efforts to repatriate the shah's wealth, the end of the U.S. freeze on Iranian assets, an American pledge not to intervene in Iran and some kind of gesture from the United States acknowledging its role in returning the shah to power in a 1953 coup and maintaining his authority for another 26 years. The details would then be left for U.S.-Iranian negotiations, said the official, who felt there was a fair chance to get an agreement and release of the hostages before the U.S. election campaign heats up in September.

It is likely to be difficult for President Carter to make any substantial concessions to Iranian sensitivities when he is in the midst of the campaign.

The more pessimistic view is that the parliament will order the trial of at least some of the hostages on charges of spying, a move that would probably cause considerable difficulties in reaching a compromise.

One hopeful indicator has been the disappearance of the issue from the limelight in both countries since shortly after the abortive American rescue mission in late April. Iranians seem to have virtually forgotten about the hostages, who are rarely mentioned in conversations.

The hostages reportedly have been divided up and scattered around the country. The government news agency said today that an unspecified number were moved from the western city of Hamadan, where an alleged coup plot was uncovered last week.

Bani-Sadr has long sought to end the hostage crisis but has been blocked by hard-line clerics who have a majority in parliament and support the militant students who hold the embassy.

In his interview today he noted that the seizure of the embassy had caused the country more harm than good, but he added without explaining that sometimes such questions are of secondary importance to a nation.

He noted that Iran had overcome the effects of economic sanctions imposed by the West and could continue to do so.

The president said he expected to present the prime minister and Cabinet to parliament in the next week but he acknowleged that there might be difficulty in gaining the legislators' approval.

"If the Majlis doesn't agree on the prime minister, another will be chosen," he said.

The president abandoned his first choice, liberal National Front member Adm. Ahmad Madani, because of opposition from the clerics. Bani-Sadr has reportedly settled for a compromise candidate, Hassan Habibi, spokesman for the Revolutionary Council, which serves as the nation's legislature until the Majlis takes over.

Parliament has been in session seven weeks but thus far has only examined members' credentials, rejecting a number for alleged involvement in the shah's regime.

The Revolutionary Council met tonight but discussed neither the premiership nor dissolving itself, as required to make way for the Majlis, Habibi said.

Meanwhile, two cousins of Shahpour Bakhtiar, the last premier named by the shah, and a former Cabinet minister were arrested for alleged involvement in last week's abortive coup designed to bring Bakhtiar back to power.