The Carter administration, seeking a way to force the pace of efforts to free the American hostages in Tehran, is actively considering a new try at reviving its long-postponed plan to impose economic sanctions against Iran, reliable sources said yesterday.

Although they said that President Carter still has not made a decision to go ahead, they added that the possibility of mounting a renewed sanctions campaign was among the chief topics discussed by Carter and his top advisers during their foreign policy review at Camp David last Saturday.

According to the sources, there is a strong feeling within the administration that Carter has to give a signal both to the Iranians and a potentially restive American public that there are limits to how long he will allow the hostage crisis to drag on.

The sources said that attitude has been prompted by the repeated assertions of Iranian authorities that the fate of the hostages will not even be considered before May, when the new Iranian parliament convenes.

In addition, the sources continued, the feeling that some kind of U.S. move is required has been reinforced by Iranian threats to delay the process even further because of the deposed shah's flight from Panama to Egypt over the weekend and by domestic political perceptions that Carter's reelection bid may be hurt by charges of inaction on the hostage crisis.

On the other side of the equation, the sources said, is the president's continuing conviction that the best hope of breaking the impasse rests in negotiation. For that reason they added, he is unwilling to take steps, such as threatening military action, that would undermine the shaky authority of Iranian moderates who also want to negotiate.

As a result, the sources said, the only option open to Carter is a new resort to the sanctions drive that the administration officially shelved Feb. 7 as part of its effort to demonstrate a conciliatory stance toward Iran.

At the time, the administration had pinned its main hopes for a solution on the U.S.-Iranian agreement for a United Nations commission to investigate the shah's alleged crimes and pave the way for the hostages' release.

However, the U.N. commission plan fell through when the moderate forces in the Iranian government shrank from a confrontation with the hostages' militant captors. Since then, the U.S. strategy has been to play for time in hopes that the moderates can strengthen their power and allow the U.N. commission to resume its mission.

Before the commission plan came up in January, the main U.S. weapon in dealing with Iran had been the push for sanctions.The idea was that by creating economic hardships and dislocations within Iran through trade and financial boycotts, the United States could force the Iranians to bargain.

As a practical matter, the United States has had sanctions in effect against Iran since shortly after the outbreak of the crises, when Carter froze Iranian assets in U.S. banks.

The administration then sought to broaden Iran's economic isolation by having the U.N. Security Council impose a formal trade and financial embargo against Iran. But that move was frustrated when the Soviet Union vetoed the U.N. resolution.

However, the United States did win agreement from its principal West European allies and Japan, the major potential sources for Iran to obtain credit and goods, to cooperate with Washington in an informal embargo.

Before that plan could be put into effect, though, the U.N. Commission idea became a viable alternative, and the administration shifted gears and put its pursuit of sanctions on the shelf.

That move angered some of the allies, who were not informed in advance that Washington was changing course. As a result, the sources said, some delicate fence-mending now would be required to coax the allies back into a cooperative attitude.

But, the sources said, the administration believes that if Carter chooses to take the sanctions route again, the allies will go along.