A D.C. tenants' coalition yesterday won a preliminary battle in its effort to get a referendum on the November ballot to overturn parts of the District's new rent control law, which is less stringent than the law that expired last month.

The D.C. Board of Elections and Ethics granted most of the approvals the group needs to circulate a petition. But the board said it would have to wait 10 days before giving final approvals to give opponents an opportunity to challenge its decision in D.C. Superior Court.

The proposed referendum would repeal sections of the law that allow decontrol of single-family homes as they become vacant and exempt apartments in buildings that are 80 percent vacant. It also would repeal part of the law that would phase out controls starting in 1989 if a tenants' subsidy program is in place and if the apartment vacancy rate in the city reaches 6 percent, considerably higher than the current 2.4 percent.

Time is important to the petitioners because they have only until mid-July to get 5 percent of the city's registered voters -- more than 14,000 people -- to sign the petition if the referendum is to come to a vote.

"It's a real long shot," said Gottlieb Simon, who filed the petition on behalf of the Emergency Committee to Save Rental Housing, made up of tenant and community groups. "We're working against time, we're working against the deep pockets of the landlords and we're doing something new."

But Emmett H. Fremaux Jr., elections board executive director, said it is "not by any means impossible" for the group to meet all the requirements for getting the question on the November ballot.

The old, stricter rent control law expired on April 30, when the new rent control legislation went into effect on an emergency basis. But like all city legislation, the permanent law has to go through a congressional review period, which in this case will end around July 12, depending on how many days Congress is in session.

Simon said that if the signatures are obtained in time, the provisions of the new law would be suspended until the November vote.

The new rent control law was approved narrowly in April after much controversy and over strong objections by tenant groups. Six of the 13 members of the D.C. City Council had been prepared to simply extend the old law, but in the end the looser controls gained the backing of a bare majority of seven.

A group of real estate agents, builders, apartment owners and businesses filed a memorandum of opposition to the petition yesterday and asked that the board reject it, saying there were unspecified defects in the petition and documents filed with it.