The Carter administration and Congress are only a nickel and three percentage points apart in their effort to reach a compromise on raising the minimum wage. But that could be enough to block an agreement, sources said yesterday.

Officials acting on behalf of President Carter have signaled a willingness to raise the present wage floor of $2.30 an hour to $2.60 and tie all future minimum wage levels to 52 per cent of the average wage earned in manufacturing.

This is 10 cents and two percentage points higher than Carter offered last March in a proposal that was considered too low by many congressional leaders and denounced as "shameful" by AFL-CIO President George Meany.

But it is still below what is described as the "bottom line" for Rep. John N. Dent (D-Pa.), chairman of the House Labor Standards Subcommittee, who wants at least $2.65 and 55 per cent. Dent originally proposed $2.85 and 60 per cent.

Dent, who is recuperating from surgery, has not yet responded to the White House proposal, which was conveyed privately to Congress late last week by Labor Secretary Ray Marshall, Charles L. Schultze, Council of Economic Advisers chairman, and other administration officials. But a source said yesterday Dent is expected to respond that $2.60 and 52 per cent is unacceptable.

Where that leaves the negotiations - which the administration initiated last week in an attempt to avoid an impasse and a possible veto on a sensitive political issue - is unclear.

Labor Department officials expressed optimism that a compromise could still be reached, although one said "It's getting close to the point where Carter just won't give any more." Another said Schultze and others did not leave behind much hope for further White House concessions.

"The White House is fairly inflexible on details," he said.

Officials said it appeared that Carter, not his economic advisers, was "drawing the fine lines."

If the negotiations fail, Dent could push ahead with his own proposal, which, if approved by Congress, could the administration in a take-it-or-leave-it position.