President Carter, timing his statement to coincide with several key congressional votes, yesterday denounced as unconstitutional the "legislative veto" provisions that Congress has inserted in a number of laws to curb executive authority.

In a lengthy message to Congress and a statement by Attorney General Griffin B. Bell, Carter said he will ignore the legislative veto provisions of most existing laws, and said he might veto new legislation that contains such provisions.

But the president stopped far short of threatening to provoke a constitutional test on the issue by going ahead with an action that had been vetoed by Congress.

Bell said Carter might attempt to brush aside a congressional veto on a minor matter, but not on a major policy question, such as a foreign arms sales.

The president has been troubled by the legislative veto since his first days in office, and increasingly frustrated by what he considers congressional "intrusion" into his authority. He had objected to a number of new legislative veto provisions even as he signed them into law as part of newly enacted legislation.

What prompted yesterday's outburst, White House officials said, was the prospect that Congress especially the House, will attempt to impose legislative vetoes on a number of bills that are to be voted on in the coming weeks.

The next attempt, the officials said, will come in a House vote this week on reauthorization legislation for the Department of Housing and Urban Development.

Informed of the White House statement, Sen. Frank Church (D-Idaho) said Carter appeared to be "inviting a tug-of-war with Congress."

"In my view, these laws are perfectly acceptable and ought not to be contested," Church added. "I hope the curtain is not going up on another imperial presidency."

Many of the provisions Carter objects to originated with congressional distrust and dissatisfaction over the conduct of the Vietnam was by President Johnson and as a reaction to the scandals of the Nixon administration.

Legislative veto provisions most often give one or both houses of Congress a set amount of time - usually 60 days - to overturn some executive action, such as the imposition of a new regulation. Perhaps the best-known of these is the Arms Export Control Act, which gives Congress 60 days to overturn foreign arms sales proposed by the administration. It was under this law that some in Congress sought unsuccessfully earlier this year to block the sale of warplanes to Saudi Arabia.

According to the White House, at least 48 legislative veto provisions have been enacted in the last four years, a trend that Carter said "represents a fundamental departure from the way the government has been administered throughout American history." Under the Constitution, the president argued, the veto is a power of te executive, not Congress.

Bell said the issue will have to be settled eventually by the Supreme Court, although there is no immediate prospect of such a high court test.

In his message to Congress, Carter proposed adoption of "report-and-wait" provisions rather than legislative vetoes.Under such provisions, the president would report a proposed action to Congress and then wait a specified time before implementing it. During the time, Congress could enact legislation, subject to the president's veto, blocking the action.