WASHINGTON -- The White House is in serious discussions over legislation long opposed by many Republicans to guarantee that insurance for mental health disorders is as comprehensive as that offered for other illnesses.

A White House official said Thursday that President Bush planned to discuss "mental health parity" at an event Monday in New Mexico, home of Republican Sen. Pete Domenici, who has championed the cause for many years. It was unclear whether he would announce a legislative deal, endorse a set of principles or just discuss the issue in general terms. The official cautioned that no deal has been reached on legislation, which is sharply opposed by business groups for fear it would increase the cost of health insurance significantly.

House Majority Leader Dick Armey is open to considering it, given the president's interest, said Armey's spokesman, Terry Holt.