A federal judge has issued a formal order striking down two provisions of the District of Columbia's initiative and referendum law, clearing the way for a possible citywide vote next May 6 on the legalization of gambling in the city.

U.S. District Judge Louis F. Oberdorfer issued the order late Tuesday. It declared unconstitutional provisions that prohibit the hiring of people to collect signatures on initiative petitions and limiting of individual campaign contributions on ballot issues to $1,000.

The ruling had been sought by the D.C. Committee on Legalized Gambling, whose members had faced possible prosecution for their admitted hiring of about 50 youths last summer to collect signatures on petitions seeking a vote on the gambling issue.

The petition drive did not yield enough signatures to get on the Nov. 6 ballot, and was recently renewed in hope of qualifying it for the District presidental primary on May 6.

Oberdorfer had said during a court hearing Tuesday that he would strike down the antihiring and contribution provisions.

In his order, he declared that the provisions violate the rights of committee members to free expression under the First Amendement.

"Unless and until the offending provisions are repealed," he wrote, "there remains the risk, however, remote . . . [of the filing of] a criminal case. Therefore, he said, the provisions cannot be enforced because they are unconstitutional.

The D.C. Board of Elections and Ethics has set a new deadline of Jan. 6 to file petitions for the May election.To qualify for the ballot, the measure's sponsors would have to produce more than 12,000 valid signatures or city voters.