The Senate again refused to stop a Republican filibuster on campaign-finance legislation yesterday, and Majority Leader Robert C. Byrd (D-W.Va.) said he is preparing an alternative the GOP will not be able to reject.

The Senate voted 45-to-43, 15 short of the number needed, to end the filibuster in its third week. It was the fifth time the Senate has refused to topple the GOP-led barrier.

Republicans have blocked action on a bill, sponsored by Democrats, which would provide partial federal financing of Senate campaigns for candidates who accept spending ceilings, which would be set for each state.

Byrd said he is working on a revised package of changes and indicated that it would reduce the role of public financing.

"To refuse it would show precisely what they are opposed to, and that's campaign-spending limits," Byrd said of his revision.

Senate Minority Leader Robert J. Dole (R-Kan.) said the GOP cannot agree to spending limits because "we would be giving away a good opportunity to make any headway in the one-party states. We're ready to negotiate, but we're not willing to negotiate away the future of our party."