Sponsors of the nation's new campaign finance law said Tuesday they were filing suit to try to overturn the Federal Election Commission's regulation plan for the law's restrictions on political "soft money.''

The law's House sponsors, Reps. Christopher Shays, R-Conn., and Marty Meehan, D-Mass., say the law is clearly meant to prohibit national party committees, federal candidates and federal officeholders from soliciting or spending the unlimited corporate and labor contributions. They contend that rather than enforcing that ban, the commission is opening loopholes.

In addition to suing in federal court in Washington, Shays and Meehan planned to introduce a House resolution stating Congress' disapproval of the commission regulations. The new law takes effect Nov. 6.

"The loopholes created by the Federal Election Commission operate separately and in combination to resurrect elements of the soft money system that Congress, on behalf of the American people, intended to put to rest,'' the congressmen and the two lead Senate sponsors, John McCain, R-Ariz., and Russ Feingold, D-Wis., said in a written statement.

McCain and Feingold said they would try to overturn the FEC rules in the Senate and would file a court brief supporting the Shays and Meehan lawsuit. They said Senate ethics rules made it difficult for them to join the lawsuit.

"Make no mistake, in the long run we will prevail, because the people want to take back their government from the special interests,'' Meehan said.

The decisions drawing the sponsors' criticism were approved by one Democrat and three Republicans on the FEC, which consists of three Democratic and three GOP commissioners.

The four commissioners criticized by the sponsors have said the law leaves the FEC with considerable latitude when interpreting it, and their goal was to establish clear standards for candidates, donors and political parties.

Shays and Meehan said the FEC regulations their lawsuit challenges include ones that would:

— Let federal officeholders and candidates continue raising soft money for state and local party committees by speaking at their fund-raisers. The new law lets state and local party committees continue raising soft money for certain purposes if state law allows it.

— Impose too narrow a test to determine whether a lawmaker is violating the soft money solicitation ban. Under the FEC rules, the only way a federal candidate or officeholder could violate the solicitation ban would be by explicitly asking for soft money.

— Give the national parties until Nov. 6 to establish new entities that could continue raising and spending soft money after the law takes effect.

— Let federal officeholders continue operating political action committees known as "leadership PACs'' financed with soft money. Officeholders use such PACs to assist their political parties and candidates.

— Too narrowly define the federal election activities that state and local party committees would be barred from spending soft money on.