Attorneys for the all-male Burning Tree Club in Montgomery County have asked that a sex discrimination suit filed against the exclusive Bethesda country club by Maryland's attorney general be thrown out of court.

Former U.S. Attorney General Benjamin R. Civiletti, now in private practice and representing Burning Tree, argues that Maryland Attorney General Stephen H. Sachs should be suing the state's department of Assessment and Taxation, and Sachs himself as the person responsible for the legal affairs of government departments.

The tax department made an agreement with Burning Tree in 1978 to allow a tax exemption for the club even though it did not admit women members, Civiletti points out in papers filed last week in Montgomery County Circuit Court. (In return, the club promised to maintain its grounds as open space.)

For Burning Tree, the exemption has been considerable, resulting in a property tax cut from $156,008 to $25,695 in 1981, according to court papers.

Sachs, who was not attorney general when the 1978 agreement was made, filed the lawsuit against the club last month, seeking to cancel the tax break because the club discriminates against women in violation of the 1972 Equal Rights Amendment to the state constitution.

At the same time, State Sen. Stewart Bainum Jr. (D-Montgomery), who had tried unsuccessfully three times to persuade the Maryland General Assembly to do away with Burning Tree's tax break, filed a similar lawsuit.

Civiletti argues that not only is Sachs suing the wrong defendant, but also that Sachs is faced with an "irreconcilable conflict" of interest because Bainum named the state of Maryland as a codefendant in his suit against Burning Tree.

Therefore, Civiletti contends, the state attorney general could find himself arguing both sides of the same issue.

Yesterday, Sachs' assistant attorney general who is handling the Burning Tree case, Diana G. Motz, said her office is not involved in a conflict of interest.

An attorney general's "first allegiance is to the Constitution," she said.

If the courts agree that the tax break is unconstitutional, Motz said, the contract between the tax department and Burning Tree would then be invalid.

Motz said the attorney general was obligated to try and get the tax break removed or risk being sued himself.