Kenneth Starr, the prosecutor in the infamous Monica Lewinsky White House scandal, is heading up a legal team challenging US accounting rules on behalf of a pro-business Republican lobbying group.

Starr will represent the Free Enterprise Fund, which opposes Sarbanes-Oxley, claiming it is in breach of the US Constitution.

The Fund filed a lawsuit on Tuesday in a federal court in Washington against the Public Company Accounting Oversight Board. arguing that it violates the US constitution's mandated separation of powers among the three branches of government.

Mallory Factor, a merchant banker in New York and a fundraiser for president George Bush, is chairman of the group.

The group will argue that the makeup of the accounting board violates the separation of powers doctrine because its members aren't appointed by the president and cannot be removed by him, and Congress cannot control its budget.

The chairman of the oversight board and the other four directors are appointed by the Securities and Exchange Commission, an independent federal agency; the accounting board is funded by fees on publicly traded companies according to their size.

Christi Harlan, a spokeswoman for the PCAOB, said she had no immediate comment to make because the board had not yet seen the lawsuit, Associated Press reported.