A lawsuit challenging the constitutionality of the new federal sentencing guidelines, which apply to people convicted of crimes committed after Nov. 1, was filed in federal court here yesterday, and the chairman of the group that wrote the guidelines said he welcomed the action.

"I'm delighted that a lawsuit has been filed this year so that as soon as possible this issue can be finally resolved," Judge William W. Wilkins Jr., chairman of the U.S. Sentencing Commission, said in an interview.

"Any major piece of legislation is going to be challenged," Wilkins said. "The filing of this lawsuit was inevitable, expected and is necessary. Now we should be able to get a decision from the Supreme Court some time next year."

The suit, filed by the Public Citizen Litigation Group on behalf of federal public defender groups in San Diego and Nashville, contends that the guidelines are unconstitutional because Congress improperly delegated legislative duties to the commission, a judicial body.

The delegation of the powers, as well as the method of appointment "The filing of this lawsuit was inevitable, expected and is necessary."

-- Judge William W. Wilkins Jr.

of commission members, vio- lated constitutional provisions for separation of powers, the suit contends.

The two groups, Federal Defenders of San Diego Inc. and Office of the Federal Public Defender for the Middle District of Tennessee, have asked U.S. District Court Judge Stanley Sporkin to declare the guidelines unconstitutional because of possible ethical problems the suit may present for attorneys.

The suit alleges that 90 percent of those sentenced under the guidelines, which were designed to eliminate disparity in sentencing, will receive harsher penalties. That means that 10 percent should receive lesser sentences. The attorneys said that they will not be able to challenge the guidelines and at the same time represent clients who might receive harsher penalities if the guidelines are overturned.

"We think the criminal justice system as a whole needs to have this issue resolved immediately," said Alan B. Morrison of the Public Citizen Litigation Group. "With 40,000 people sentenced every year, not counting petty offenses, you are talking about a potential mess if these things are declared unconstitutional down the road."

Public Citizen mounted a successful challenge to a portion of the Gramm-Rudman-Hollings budget reduction law on similar separation-of-powers grounds. Congress revised that law last December.