A coalition that expects to spend $50,000 or more lobbying for a mandatory seat belt law in Maryland kicked off its legislative campaign Monday with leaders of the drive saying they expect a tough battle in the General Assembly.

"It's not going to be easy," George S. Wills, a coordinator for the Maryland Committee on Safety Belt Use, said at a news conference.

Wills said he expects considerable opposition on the Senate floor when the bill is reported out of the Judicial Proceedings Committee some time this week.

Several versions of the seat belt bill have been introduced in the House and Senate. The version approved by the Judicial Proceedings Committee carries a $20 fine and would require the driver and passenger next to the door in the front seat to wear belts.

Michael McDonald, chairman of the seat belt committee, said the coalition expects to spend $50,000 or more on its campaign, with most of the money coming from Traffic Safety Now, a national organization set up to push for mandatory seat-belt laws around the country.

The major participants in Traffic Safety Now are the nation's automobile manufacturers, which are pushing for such laws at least in part to avoid a requirement that they install air bags in automobiles in the future.