When conservative activist Patrick B. McGuigan learned about a planned Justice Department grant to the National Coalition Against Domestic Violence, he dashed off a letter to Attorney General Edwin Meese III.

McGuigan also pressed his case with Rep. Mark D. Siljander (R-Mich.), who urged Meese not to award money to "pro-abortion, pro-lesbian, anti-Reagan radical feminists."

Meese decided to postpone awarding the grant, and it has remained under review for nearly two months.

"I am unashamedly opposed to funding the left with grant money in the Reagan administration," said McGuigan, an official with the Free Congress Foundation. "I've been tracking the national coalition for years. This organization is very hard-core on the liberal end of the spectrum."

More may be at stake than a $625,000 grant to aid shelters for battered women. It is the first time since Meese became attorney general in February that the conservative movement has publicly asked him to reverse one of his deputies -- Assistant Attorney General Lois H. Herrington, who approved the grant -- on a social issue important to the right.

The split in conservative ranks was underscored when Maureen Reagan, the president's daughter, criticized Meese for blocking the grant.

After 23 House conservatives joined Siljander in signing a letter opposing the grant, liberals fought back. Twenty-three generally liberal senators, led by Frank R. Lautenberg (D-N.J.), told Meese they were "deeply disturbed" that he was holding up the award.

Sharon Parker, executive director of the National Coalition Against Domestic Violence, said the issue is not the grant, which would finance education and training programs aimed at improving services for battered women. The conservative movement, she said, has "just discovered us as a new target."

Parker said the coalition is an advocacy group representing most of the nation's 877 women's shelters and local government and community groups. She said Siljander's letter to Meese had unfairly tagged her group with "a boilerplate label," radical lesbians.

"There are no policies in this organization that say we're for abortion or against Ronald Reagan," Parker said. "We deal with domestic violence."

At a news conference yesterday, Meese said only that the grant is undergoing a "review process" in response to "a complaint."

The grant had been approved by Herrington's office and was to be announced at a Kennedy Center ceremony in June.

"Any time you've got an uproar among members of Congress, it behooves you . . . to take a second look at it," Justice Department spokesman Pat Korten said.

"We're not in the position of conducting a political or philosophical litmus test on everyone who receives a federal grant. We do want to make sure it's a legitimate program and the money is appropriately spent," he said.

Parker said the coalition has a lesbian task force that deals with discrimination against lesbian shelter workers. She said its members are often invited to speak to local groups about fear of homosexuals.

Critics cite this as proof of the coalition's pro-lesbian stance and complain that the federal money would triple its budget.

"The grant is a networking grant," McGuigan said. "Not one dime is going to go to help battered women. It's going to help the leadership of women's shelters."

Herrington, ordinarily a favorite among conservatives, said in a letter to Siljander that the grant's opponents "disapprove of the views and lifestyles of some who give their time and energy to this movement. This charge is misguided." She said that the national coalition "is the leader in this emerging area" and that to ignore it would be "demonstrably foolish."

Siljander has been less steadfast.

He told Meese July 24 that he had dropped his objections to the grant. Five days later, he retracted that, saying the earlier letter "does not accurately reflect my position."

Robin Luketina, Siljander's chief of staff, said Siljander decided to "drop back and punt" after hearing conflicting arguments about the grant.

Another aide said Siljander is concerned about the coalition's "radical aspects."