Democratic presidential candidate Edward M. Kennedy said yesterday that the major industrial nations probably will not cut diplomatic ties with Iran as the United States has asked them to do, unless this country promises to make up the oil supplies those nations stand to lose through a break with Iran.

Kennedy added that if the United States should provide oil to its allies, American consumers would have to make do with a smaller supply at home. He criticized Carter for failing to prepare the American people for that possibility.

The issue came up yesterday in an interview with reporters and editors of the Washington Post as the Massachusetts senator discussed, in casual, conversational tones, the Carter administration's effort to convince major allies to join the United States in breaking ties with Iran.

"Does this administration in . . . trying to get help from the allies, guarantee them an energy resource if they cut off their diplomatic initaiatives?" Kennedy said. ". . . I don't think that you could expect that you'd get a positive response unless you do.

"I think that's going to be the first thing, I would think, that [British Prime Minister] Margaret Thatcher or [West German Chancellor Helmut] Schmidt or anybody else would say -- 'Look, they're going to cut off our oil.' . . . If [the Iranians] cut off, are you prepared to send to Congress . . . Kennedy's gas rationing bill? . . . Are the American people prepared [for it]? Are the people even talking about it or being prepared for it?"

In his most recent efforts to win release of the American hostages in Tehran, Carter has called on principal U.S. allies to impose economic sanctions against Iran, and if those sanctions don't work, to sever diplomatic relations.

The Iranian government says it will cut off oil supplies to any country that takes either step. A loss of Iranian oil could mean serious disruptions for Western Europe or Japan.

A White House spokesman said yesterday the Carter administration has not promised to make up for such losses. "There's been nothing specific in the way of here's our quid for your quo," said Alfred Friendly Jr., who works in the office of national security adviser Zbigniew Brenzinski.

Friendly noted that the United States is a party to an International Energy Agency agreement requiring international sharing of oil in case of a serious global shortfall. It is not clear whether an Iranian oil cutoff would trigger that sharing plan.

Kennedy again criticized Carter yesterday for permitting the deposed shah of Iran to enter the United States last fall without taking precautions to protect the U.S. Embassy in Tehran from mob retaliation.

Asked what he would have done as president if the shah had asked to enter this country, Kennedy gave a long response that set forth a balancing test between "a very proud tradition . . . of asylum" and "the protection of lives of Americans here and overseas" The answer would depend, he said, on "a balance of different factors."

Kennedy was asked the same question -- "Would you have admitted the shah?" -- at a campaign stop in Brooklyn three weeks ago. He gave a shorter answer then: "No."

As he has on the stump, Kennedy yesterday ridiculed Carter's efforts to control inflation, taking a poke at the president's decision to announce his latest antiinflation program in a televised speech on Friday afternoon.

"The president marshals national opinion on the economy at 4 o'clock on a Friday afternoon?" Kennedy said scornfully. "You mention that in any union hall and they'll laugh. They don't think the president is serious. And I don't think he is serious about it."