Advocates of a tougher seat belt law in Virginia will make one last attempt to change the current law in a closely divided House of Delegates committee on Tuesday, setting up another crucial vote for the measure's most powerful ally, Gov. Mark R. Warner (D).

Members of the House Transportation Committee are scheduled to vote on a bill passed by the Senate that would allow police to enforce the state's seat belt law as a "primary" offense, which means officers could ticket offenders without having pulled them over for another reason. A House version of similar measure lost on a 10 to 10 tie last month despite intense lobbying by Warner.

Warner administration officials and Democratic lawmakers said that, while the governor still supports the legislation, they believe it will be difficult to win in the House committee and then on the House floor. Bills must pass both chambers before they can go to the governor for signature.

"The administration continues to work with members of the House Transportation Committee to fight for its passage," said Ellen Qualls, Warner's spokeswoman. "We recognize there are entrenched viewpoints, and this is an uphill battle on the House side."

Two Democratic committee members who oppose the measure and could be key to its fate on Tuesday said they have not discussed it with Warner in recent days. Dels. Jackie T. Stump (D-Buchanan) and Albert C. Pollard Jr. (D-Westmoreland) did not vote in committee last month.

"While making it clear they still want my support, they understand the political landscape and the partisan issues," Pollard said of the administration.

Stump said that health and safety advocates lobbied hard for the bill today but that Warner has not called him.

He said his only conversations with administration officials were "passing in the hallway."

"I guess they figure the votes are just not there to do it," he said.

Both delegates said they intend to vote against the bill.

Advocates for the seat belt measure dismissed those comments as too pessimistic. After a day of intensive lobbying, they said they believe the committee might pass the measure Tuesday. If it does, proponents say they have the votes on the House floor, despite the gloomy administration prediction.

"We get the sense that it's a close vote. But we don't get the sense that we've lost any momentum," said David Kelly, a spokesman for the Virginia Coalition for Child Safety. "It's going to be a close vote on the House floor. But it's a winnable vote, and it's not one we are ready to give up on."

For Warner, a surprise win in committee would be welcome. Last week, Republicans defeated the Democratic governor's proposal to allow future chief executives to serve consecutive terms. And the GOP, which has a majority in both chambers, got the support of some Democrats to pass a repeal of the estate tax by veto-proof majorities.

Warner has had more success with his agenda to restructure state government, most of which has sailed through both chambers. He has been stymied on such high-profile, controversial measures as the seat belt bill.

Virginia requires the use of seat belts, but officers are not allowed to ticket offenders unless they stop the driver for another reason. Law enforcement advocates have tried for years to allow officers to give out seat belt tickets without that restriction.

Advocates say giving police that power could save 120 lives and prevent 2,000 injuries each year in Virginia. Opponents say the proposed law amounts to legislating common sense and is an unwise government intrusion.

"Of all the laws on the books, now they want to make one that covers stupidity," said Del. Thomas D. Gear (R-Hampton).

Republican and Democratic lawmakers who support the tougher law launched their final bid today to save it for the year. In a morning news conference, they emphasized the measure's financial benefits, saying Virginia citizens pay millions for the health care of victims in avoidable accidents.

"The economic costs almost rival the human costs," said Sen. William C. Mims (R-Loudoun). "We are talking about costs that amount to the tens of millions of dollars."

Mims said Warner told him late last week that the seat belt measure is important to him. He said the governor indicated he would push to help get it passed.