Gov. Buddy Roemer has decided to move from the Democratic Party to the GOP, his chief of staff and a Republican legislator said.

"It is not a matter of if, it's a matter of when," chief of staff P.J. Mills told The Times-Picayune in a story published Saturday. "It is now a case of working out the details. This is a big thing for him."Roemer and spokesman Rusty Jabour have refused to confirm or deny reports that Roemer is changing to the Republican Party, though Roemer scheduled a news conference Monday to announce his decision and told listeners at an appearance Friday that "you might be surprised" at the outcome.

Mills did not return a call Saturday, asking Jabour to return it instead. Jabour said he could not say what Roemer's decision was.

Mills told the newspaper that Roemer and a close-knit circle of advisers met until almost midnight Thursday thrashing out the pros and cons of the switch.

"He is changing his registration . . . I have had very serious discussions with him about it. He initiated the discussions," said state Sen. John Hainkel, a Republican from New Orleans.

Roemer said he has spoken to White House officials over the last five months, dealing mainly with Chief of Staff John Sununu. He said he has not discussed it personally with President Bush.

National Republican officials are reportedly intensely interested in the change.