The American Civil Liberties Union, which defends the rights of the tobacco industry to advertise its products, has accepted more than $500,000 in contributions from cigarette companies over the past six years, according to a report sponsored by several public interest groups and released yesterday.

The report, by former Washington Post reporter Morton Mintz, says that ACLU executive director Ira Glasser first solicited money from Philip Morris Co. in 1987, a year after the ACLU began publicly opposing efforts to ban advertising by cigarette companies. The company gave the group $75,000 in 1987 and each of the next three years, and $100,000 a year in 1991 and 1992.

R.J. Reynolds Tobacco Co. also contributed an undisclosed sum to the ACLU, and the Tobacco Institute, the industry's lobbying arm in Washington, gave $1,000, the report disclosed, attributing the information to Glasser.

Mintz criticized the ACLU's practice of not disclosing tobacco industry contributions. "The effect is to add concealment to what in shorthand may be called advocacy and money," he said. "The troika is clearly a conflict of interest."

ACLU spokesman Phil Gutis denied any link between tobacco industry grants and his group's defense of tobacco advertising, saying that commercial First Amendment rights are a fundamental and historic concern of the ACLU. He also said that there was no relation between the ACLU's 1986 testimony and the first contribution.

"If we were to try to screen the involvement or the beliefs of all our contributors, we'd be in big trouble," said Gutis. "Where do you draw the line? It's political correctness run rampant. We are delighted when anyone supports the work we do."

Gutis said the ACLU does not reveal the names of its contributors or members in order to protect their right to privacy. He noted that tobacco industry money represents less than 1 percent of the group's annual budget.

Philip Morris spokesman John Boltz said the company supports the ACLU because "they're nationally recognized advocates of many of the issues we feel strongly about. Adult consumers should be able to receive information about legal products without further abridgement."

A Reynolds spokesman was not available for comment.

The 36-page report by Mintz cited examples of testimony by ACLU officials before congressional committees considering legislation to restrict tobacco ads.

When senators attempted last year to cut the tax deductibility of tobacco ads and promotion, ACLU officials helped head off the proposal by circulating "Dear Senator" letters questioning the constitutionality of such a measure, Mintz reported.

The report was published by the Advocacy Institute, an anti-tobacco group, and sponsored by the Center for Science in the Public Interest, the Coalition on Smoking or Health, Ralph Nader, Public Citizen and the Trauma Foundation.