Federal regulators say people now registered with the national do-not-call list should see telemarketer calls decrease -- assuming the telemarketing firms comply, which an industry group has asked them to do.

But the Federal Trade Commission is discouraging more people from signing up while telemarketers fight the list in court.

DO NOT CALL LIST Sign Up Q&A Share Your Thoughts Are You Still Getting Calls?

The head of the FTC said the agency is working on shutting down the registration process. Chairman Timothy Muris said registration has surged because of publicity over the legal fight.

The FTC's main system for filing complaints against telemarketers has also been shut down. Muris says that doesn't mean consumers won't be protected -- it will just be more difficult to register a complaint.

Judge Leaves Order In Place

Earlier, a federal judge said that despite President George W. Bush's signature, the FTC still doesn't have the power to enforce the measure.

The Denver judge denied a FTC request to suspend his decision while the agency appeals.

U.S. District Judge Edward Nottingham also warned the government that involving the Federal Communications Commission will spark more legal action for "trying to skirt the order."

He said that his ruling last week clearly prohibits the FTC from operating the registry on free-speech grounds, and that the law prevents any indirect actions to get around that.

The FCC said Monday it would take action against telemarketers that violate the do-not-call list that was to go into effect Wednesday.

Several court challenges are swirling around the registry. The bill Bush signed was intended to alleviate concerns of a judge in Oklahoma that the FTC did not have authority to enforce the list.

More than 50 million phone numbers have been registered.