Senate Majority Leader Robert C. Byrd (D.W.Va) said yesterday he will not move to end the filibuster against the administration's hotly contested labor law revision bill until senators return from their Memorial Day recess next month.

Filibuster leaders had beenm expecting one or more votes to cut off debate - votes they were almost certain to win - before the recess starts next Friday.

Byrd's move means that wavering senators will not be put on the spot before going home, where both business and labor are gearing up massive "grass-roots" lobbying efforts.

Although some apponents of the bill interpreted Byrd's move as a sign of weakness from administration forces, AFL-CLO official Victor Kamber said it will undercut the filibusterers' argument that debate was being terminated prematurely.

"The reaosn I'm waiting is to give ample time for debate on the measure," said Byrd as the talkation druned into its third day. He said he expects the first colture petition to end the filibuster to come sometime after the Senate returns June 5, but did not specify when it will be filed.

The Bill's proponents have conceded that they expect to lose their first attempt to get the 50 votes necessary to end debate. But they say they expect to pick up strength as time goes on and may go over the top by the third or fourth vote, claiming that they will ultimately have 63 or 64 votes.

Even if cloture is invoked, as some opponents concede it may be, opposition forces are prepared to continue their delaying tactics with hundreds of amendments aimed at forcing the Democratic leadership to withdraw the bill.

The leadership has said it will not withdraw the measure. Asked yesterday about the status of other legislation, Byrd said, "I'm not projecting anything beyond labor reform. That will be with us for a while."

The bill, proposed by the White House and backed by labor over intense opposition from business groups would set deadlines for union representation elections and stiffen penalties for illegally thwarting organizing and bargaining campaigns. A somewhat stronger version of the bill was passed by the House last year.