President Reagan and his administration were described yesterday as being "outraged" by reports of acts of brutality on the American hostages.

But a State Department spokesman declared the administration nevertheless plans to carry out this country's remaining obligations under the complex agreement that led to the hostages' release if a current review of its provisions finds them fully consistent with law.

Throughout the day there were official expressions of concern for the way Iranian militants treated the 52 hostages during their 14 months captivity.

Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) said Congress would hold hearings to "inquire fully into the brutal treatment" of the 52, though he suggested they not start until "passions have subsided" a little.

Former vice president Mondale, who delivered to the White House a four-page handwritten report on the status of the hostages by former president Carter, told reporters that Reagan was "outraged" by the "by the "barbaric" treatment it described.

Vice President Bush said the Carter letter, written after he saw the freed hostages Wednesday in West Germany, was "powerful . . . something that cause the president great concern."

"It's apparently worse than they had expected, a lot worse," Bush said, "and something every citizen across this country is going to be outraged by."

While Carter and Mondale both added to the general indigation with the report on the hostage treatment, they continued to stress the need to follow through on the agreement that was hammered out in the closing hours of their administration.

"If they are barbaric," Mondale said, "we must demonstrate the differences. This agreement is in our interest . . . it is a good bargain for our country. It protects all the claims of the claimants."

Assistant Secretary of State William Dyess summed up the tension for the new administration being created by growing reports of torture by saying they "well not make it any easier" for Reagan to follow through on the obligations negotiated by the Carter officials.

But Dyess quickly added that he "did not mean to imply that the [torture] reports will have any influence" on Reagan's eventual decision.

Reading from a prepared statement, Dyess told reporters yesterday, "This administration, consistent with domestic and international law alike fully intends to carry out the obligations of the United States."

Dyess' position was supported by a new Reagan White House aide who stressed that meeting demands of "the law" was the main test being applied to the agreement during the current review of its provisions.

Dyess said the review may be completed within a few days, but another State Department official suggested it could take longer, "perhaps weeks." Under trhe agreement, the United States has 30 days from the time of the signing (Jan. 19) to begin court actions that would lead to release of additional $4 billion in frozen Iranian assets.

One focus of concern was whether the agreements permitted Iran to collect the roughly $400 million of military equipment and spare parts that had been frozen along with other assets.

Defense Secretary Caspar Weinberger was reassured yesterday by Carter administration officials, sources said, that the Carter executive order permitting Iran to order delivery of its purchased material specifically requires new approval by the State Department before the material can be shipped.

The Reagan administration's delay of publication of the 10 executive orders implementing the agreement ended yesterday and officials said the documents would be published today in federal register.

At the Treasury Department, sources sid regulations implementing those orders probably would be released today.

In New York, lawyers representing approximately 100 claimants seeking more than $1 billion from Iran for back debts or seized property released a letter they sent to Reagan asking for a hearing before any regulations are released.

The Carter excutive orders, the letter states, "raise serious constitutional and other legal questions."

The head of the lawyers group, Lawrence W. Newman, represents, among other claimets, the Sedco Inc., which operated oil-drilling platforms off Iran and was involved in ventures with the Pahlavi Foundation, which handled investments for the late shah and his family.

Sedco's founder was Texas Gov. William Clements, one of Reagan's close personal and political friends, and it is run by Clements' son.

Sedco has filed a court claim seeking recovery of $175 million from Iran for expropriation of its equipment and breach of contract.

Newman said yesterday that it could be argued that Carter exceeded his presidential authority in the way the claimants have been handled.

Under the agreement, Sedco and the other claimants would have their American suits nullified and thereafter would have to take their claims to an international tribunal which is to be established.

Top former Carter administration officials who had been involved in the negotiations with Iran said yesterday they believed the agreement and the manner in which the claimants are to be treated meet "every test of U.S. contract law," as one put it.

They also welcomed the study by the Reagan administration.

As one former official said: "They need to learn it now because they never took the time to look into the details earlier."

These former Carter aides expect the uproar over the agreement to calm down in the next week, and they see the Reagan implementation beginning after that.

"We have no reason to think that at the highest level there is anything but an intention to fulfill the obligations," one Carter aide said yesterday.

One of the most distasteful provisions under the agreement that the Reagan people will have to enforce is the requirement tht the U.S. government prohibit the hostages or their families from filing claims against Iran.

Instead, under the executive orders signed by Carter, a president's orders signed by Carter, a President's Commission on Hostage Compensation will be created with a requirement that it report within 90 days on whether the government should "provide compensation to United States nationals who have been held in captivity outside the United States . . . ."

The Reagan administration indicated that, with regard to at least one provision of the agreement, it may be looking for ways to blunt the effect of the Carter exective orders.

The trade embargo placed on Iran at the time of the embassy seizure and expanded several months later was ended Monday under provisions of the hostage-release agreement and Carter's implementing order.

State Department spokesman Dyess said yesterday, however, that despite the removal of the embargo, "trade policy with Iran is under review." His statement raised the possibility that new restrictions may be proposed.

On Capitol Hill, Sen. Dennis DeConcini (D-Ariz.) and Rep. Paul Findley (R-Ill.) introduced resolutions pledging support for any decision by Reagan to abrogate the remaining terms of the hostage-release agreement.

DeConcini's resolution would put the Senate behind any decision Reagan "may make in refusing to carry out the agreement."

Findley's proposal would express "the sense of he Congress that the president would be justified in renouncing all or part of the agreement if he finds it is in the interest of the United States to do so."

Sen. Henry M. Jackson (D-Wash.) told the Senate yesterday that Reagan should quickly develop a policy to "make it clear to friends and adversaries alike around the world that the U.S. government's reponse to Iran's hostage seizure is not a governing precedent for the future."

State Department spokesman Dyess told reporters that the administration is reviewing its policy for handling terrorism.