Sen. Alfonse D’Amato’s one-day $37,125 stock bonanza put him back before the Ethics Committee on Tuesday after a Ralph Nader watchdog group filed a formal complaint.

The Congressional Accountability Project charged that the New York Republican “may have violated Senate rules and federal law” in the 1993 deal with a Long Island brokerage firm.

A newly released government report charges that Stratton Oakmont Inc. gave D’Amato special treatment in permitting him to invest in a computer company stock that more than tripled in value in a matter of hours.

At the time, D’Amato was the top Republican on the Senate Banking Committee, and the Securities & Exchange Commission was probing Stratton Oakmont.

“Stratton Oakmont gave Senator D’Amato a $37,125 favor at a time when they were in dire need of assistance from the Senate Banking Committee,” said project director Gary Ruskin.

“This is nothing but politics,” D’Amato said. “It’s obvious people are trying to embarrass me.”

Founded by Nader, the project also has filed ethics complaints against House Speaker Newt Gingrich, R-Ga.