President Reagan won a commitment from farmers' representatives yesterday to accept budget cuts that will hurt farmers in order to aid the administration's effort to control federal spending.

The farm leaders also refused to critize the president for failing to move swiftly to lift the Soviet grain embargo, an action he promised during the presidential campaign.

Jim Billington, president of the National Association of Wheat Growers, said the embargo decision "has to do with the foreign policy of this nation; with what is going on in Poland and the rest of the world."

Billington, whose wheat farmers strongly protested President Carter's imposition of the embargo after the Soviet invasion of Afghanistan, pledged to work with the administration.

Robert Delano, president of the American Farm Bureau Federation, and others in the group that visited Reagan told reporters that although they still want the embargo lifted, "farmers shouldn't be singled out" if the embargo has to continue for national security reasons. They suggested that other commodities be added to the embargo to spread the burden to other sectors of the American economy, or that new concessions be made to farmers to compensate them for the loss of sales to the Soviets.

They said, however, that they did not discuss with Reagan specific concessions that the farmers would like.

Delano told reporters that the president should be given time to make his decisions. "Give the man a chance," he urged.

"I still think it is his intention to eliminate the embargo," Delano said.

The farm leaders said Reagan did not tell them what programs beneficial to farmers are going to be cut back in the economic package he will present to Congress on Feb. 18. "All of agriculture will give up something," Delano said, in recognition of the need to aid the economy and control inflation.

Agriculture Secretary John R. Block told reporters that no decision has been made on the embargo and it will be discussed at an upcoming Cabinet meeting. The Washington Post reported after Wednesday's Cabinet meeting that Reagan will not lift the embargo for the foreseeable future.

Reagan interrupted his morning meetings for a small celebration in the Oval Office to mark his 70th birthday, and was feted at a party last night.

Spokesman for the White House and the State Department attacked a report in yesterday's New York Times that said Secretary of State Alexander M. Haig Jr. had told the European allies to disregard Defense Secretary Caspar W. Weinberger's statement that the United States is likely to proceed with production of the neutron bomb.

White House deputy press secretary Larry Seakes said the article inaccurately reported a message Haig had sent to Europe. State Department spokesman William Dyess called the article "a grossly inaccurate report."

Their main concern appeared to be to reassure U.S. allies that there would be consultation before any deployment of the weapons and to rebut the story's indication that Haig and Weinberger were in disagreement.

Weinberger had said that the United States would consult its allies.

"It is our position that the administration speaks with one voice," Speakes said. "The secretaries talk often on many subjects and they are not in disagreement." Haig's message said that it is normal for a new administration to review decisions such as whether to build the neutron bomb. Haig stressed that no decision had been made.

Weinberger said at his first news conference on Tuesday that "I think the opportunity that this weapon gives to strengthening [European] theater nuclear forces is one that we very probably would want to make use of." The Carter administration decided in 1978 not to go ahead with production of the weapon.