The White House plans a blow-out New Year's Eve party on the Mall to mark the new millennium, but Metro officials are hardly celebrating. They want the federal government to help pay the estimated $1 million cost of ferrying revelers across the region on trains and buses.

"It's a huge national event, and at least some contribution should come from those staging the party," said Chris Zimmerman, Arlington County's representative on the Metro board of directors, which will take up the issue at a meeting tomorrow. "People who throw the party should pay the band."

Metro is expecting as many as 750,000 passenger trips this New Year's Eve, more than twice the number the transit system had last Dec. 31, spokesman Ray Feldmann said. "We don't even want to call it a projection because we don't know what to expect," he said. "Basically, we've never provided service for the millennium before."

Transit officials anticipate more riders than on another traditionally busy night for Metro--July 4. Last Independence Day, Metro had 541,000 passenger trips, Feldmann said.

"We're basically providing rush-hour service on New Year's Eve--you've got almost every employee working, every piece of equipment out on the streets," Metro General Manager Richard A. White said. On a typical Friday night, 189 Metrobus workers are on duty. This New Year's Eve, 914 Metrobus workers are scheduled to work, most of them earning a premium for the holiday shift.

Metro directors sent a letter three weeks ago to the U.S. Office of Management and Budget as well as congressional delegations from Virginia, Maryland and the District, asking for federal dollars for New Year's Eve service.

"We're aware of the request and we're looking at it," said OMB spokeswoman Linda Ricci.

Metro has not sought federal money for service during other special events, such as the July 4 celebrations on the Mall, Feldmann said. "We think this is an extraordinary circumstance and that Metro is entitled to compensation," he said.

Del. Eleanor Holmes Norton (D-D.C.) said the federal government should pay the tab. "The White House has declared a separate millennium celebration," Norton said. "The millennium crowd is not coming here to see my constituents in Ward 4. They are coming here because they have been summoned by the federal government."

About 100,000 merrymakers-- including President Clinton and the first lady--are expected to flock to the Lincoln Memorial at 10 p.m. on Dec. 31 for a nationally televised New Year's Eve show that will feature performers ranging from country western stars to opera divas. As midnight approaches, a live orchestra will premiere a score by award-winning composer John Williams as images of the American century--chosen by moviemaker Steven Spielberg--play on giant screens on three sides of the Reflecting Pool.

The White House's shifting plans for the gala made it difficult for Metro to plan properly and budget for the extra service, Feldmann said. "Frankly, a lot of information about what was going to happen has just come to fruition in the last few months or weeks," he said. "Y2K we could plan for, but this millennium service stuff was not budgeted."

On New Year's Eve, Metro traditionally runs trains until 2 a.m. and buses until 3 a.m. Since 1985 it has not charged fares after midnight, in an effort to encourage people to take mass transit and cut down on drunken driving.

This year, Metro plans to run trains until 3 a.m. and buses until 4 a.m. Metro directors will decide tomorrow whether fares will be free after midnight. If the transit agency were to charge fares after midnight, it would bring in about $270,000 in revenue, leaving a net cost of $730,000 for the extra Dec. 31 service , Feldmann said.

Norton said free fares are key to a safe New Year's Eve. "We're not only going to have the normal regional resident out there," Norton said. "We're going to have all sorts of folks who think this is once-in-a-lifetime celebrating like there's no tomorrow. We don't want these folks in the streets."

If it fails to get federal help, the transit agency would spread the cost among Maryland, Virginia and the District rather than make cuts elsewhere in its budget, Feldmann said.