The Immigration and Naturalization Service plans to establish express lanes at certain border crossings to Mexico and Canada -- and charge for the expedited service.

INS spokesman Verne Jervis said the agency will inaugurate the system this spring at a few unspecified locations. It has not decided on the amount of the fee.

The pay lanes would be staffed with additional inspectors to speed border crossings, which now can take two to three hours. The service would be available for anyone who is legally eligible to cross the border.

"We are stressing that use of the fee lanes is voluntary," said Duke Austin, another INS spokesman. "There will still be non-fee lanes for those who choose not to pay."

Immigrant rights groups have criticized the revenue-raising method and said it could lead to a tax on anyone entering the United States. Such a tax, activists said, could saddle poor migrant workers, who cross the border often and are least able to afford additional expenses, with the brunt of the responsibility to pay for faster inspection service.

Cecilia Munoz of the National Council of La Raza questioned the precedent of establishing any fee, even if optional, for crossing the U.S. border. "We're living in an age when walls are coming down in other parts of the world and yet the United States is considering a fee for coming in," she said.

And she questioned whether INS can handle another new program given its current management and financial woes. The General Accounting Office, in a recent draft report on the INS, was harshly critical of the agency's administration and budget process.

"Charging fees at the border is not the way to take care of the gross mismanagement of the INS," said Mario Morean, an attorney for the Mexican-American Legal Defense and Educational Fund.

Supporters of a border-crossing toll were critical that the INS has not gone further. They said the agency is authorized by legislation passed by Congress last year to adopt a more ambitious fee program to pay for improved border security.

"They have an opportunity for an aggressive, intelligent program, and the results could provide for a permanent, effective financing vehicle for sound border security, and they're ducking for cover already," said Dan Stein, executive director of the Federation for American Immigration Reform.

Stein said quicker inspections funded by a toll would be a boon to commerce in border communities.

"The biggest detriment to trans-border commerce is the two- to three-hour wait currently encountered in cross-border excursions," Stein said. "Those who are crossing the border for legitimate reasons will be more than happy to pay for better and faster inspections. Time is money."

Stein said a toll of $2 would increase the agency's budget by 50 percent. The additional money and manpower also could be used to help control drug smuggling and violence on the border, Stein said.

But Jervis said the fees would be used solely to finance the express-crossing program.