In a move that could prove politically damaging to President Carter, the Federal Election Commission yesterday relaxed fund-raising and spending restrictions on groups attempting to draft Sen. Edward M. Kennedy (D-Mass.) for the 1980 Democratic nomination.

The commission, by a 6-to-0 vote, approved an advisory ruling that groups seeking to draft a candidate can accept individual donations of $5,000, $4,000 more than the $1,000 limit placed on regular contributions to candidates for federal office. The $1,000 limit is "not applicable," the commission said, because Kennedy is not a declared candidate.

The commission also ruled that there are no restrictions on how much money a group seeking to draft Kennedy or any candidate may spend in a state. Declared candidates, however, must still abide by a complex series of rules that limit spending.

The decision means, in effect, that an individual supporting an effort to draft a candidate could give the groups as much as $25,000 -- the maximum for all donations under FEC rules -- or 25 times as much as the donor could give a declared candidate.

"This has profound implications for the movement to draft Teddy Kennedy," said Paul D. Friedman, treasurer for a Florida draft-Kennedy group that sought the advisory opinion. "Any sizable campaign requires money. This will make it available to us."

"I think it's Katie-bar-the-door now," he added.

The decision directly applies only to the Florida for Kennedy Committee, which claims it would go out of business if the Massachusetts Democrat, who leads Carter by more than 2 to 1 in polls, became a candidate. But the decision will be used as a guide for the 14 other draft-Kennedy groups that have filed with the commission.

The FEC ruling apparently caught the White House and the Carter-Mondale Reelection Committee by surprise. There was no attempt by Carter forces to oppose the ruling before it was reached, according to FEC and reelection committee sources.

"We're not running against Teddy Kennedy, so we've avoided any part in activities that would seem to be an us-against-them battle," said Jack Walsh, the political director of the Carter reelection committee.

"It's an important ruling, a very important one. Wow," he added. "It's changed the rules. Now we'll have to respond to it in a political way."

The ruling, said a Republican National Committee spokesman, "is just one more example of having an artificial bureaucratic agency trying to regulate every aspect of the political process. It works toward inequity, not fairness."

The federal election campaign act does not place limits on "an expenditure by a person expressly advocating the election or defeat of a clearly identified candidate which is made without cooperation or consultation with any candidate or any authorized committee," said the opinion signed by Robert O. Tiernan, FEC chairman.

There was no real debate on the move. However, commission member Thomas Harris observed: "I think the result of all this is ridiculous. But it seems mandated by law. It seems like a big paradox to me."

Kennedy has repeatedly said he isn't a candidate for the presidency. But as Carter's standing in public opinion polls has continued to slide, 15 different draft-Kennedy groups in 13 states have filed with the FEC.

The strength of the groups, however, has been uneven, and even the best organized ones have found raising money difficult.

"It's hard to raise money from large givers," said Leon Shull, executive director of Americans for Democratic Action, which has endorsed such efforts. "Traditionally, most of these people like to press the flesh when they give money. Here we don't have a candidate."

It was difficult yesterday to determine how many of the draft-Kennedy groups the ruling will affect. At least one group, in New Hampshire, Democrats for a Change, has already indicated it would accept donations of up to $5,000 because it considers itself a multi-candidate political action committee. Such groups are allowed to accept such donations, but they must contribute to more than one candidate.

The other states with active draft-Kennedy groups are: Iowa, site of the nation's first precinct caucuses next year, Minnesota, New York, Illinois, Pennsylvania, Texas, Ohio, Oregon, Montana, Colorado and Indiana.

The commission refused to answer one question asked by the Florida group that could become crucial if Kennedy decides to run. That was, would contributions to draft groups count against normal limits on giving?" The commission said the question was "hypothetical."

Kennedy spokesmen refused to comment on any part of the ruling.