Patrick J. Buchanan denied reports yesterday he is preparing to leave the Republican Party to seek the presidential nomination of the Reform Party, accusing unnamed rivals of attempting to disrupt his campaign on the eve of the Iowa GOP straw poll.

"There's nothing that's changed," Buchanan said in a telephone interview. "I'm saying I'm currently focused on the Iowa straw poll, the Republican caucuses and the Republican primary states. That's the road down which I'm headed now."

Buchanan, however, signaled his disenchantment with the direction of the Republican Party and made clear his conservative convictions are more important to him than party loyalty. "What I've been saying is that I'm committed to pro-life [on abortion], to an America-first foreign policy, to a trade policy that puts American workers and manufacturers and sovereignty first," he said.

"I'm going to follow those ideas and ideals straight down the road," Buchanan added. "If the Republican Party veers off the road, that's their business. My first commitment is to my ideals and convictions. As Jack Kennedy once said, `Sometimes party loyalty asks too much,' but right now I'm going down the road as a Republican."

Buchanan, who unsuccessfully sought the GOP nomination in 1992 and 1996, acknowledged that he and his sister Bay Buchanan have had discussions with people about a possible third-party candidacy in 2000, but he described as "media hype" suggestions that he is on the verge of bolting the GOP.

"The timing is curious," Buchanan said of an Associated Press report about his intentions. "I think it is being pumped up by people who I think do not wish us well in the straw poll."

The non-binding Republican straw poll, which will be held Aug. 14 in Ames, will provide an early glimpse of the relative strengths of the GOP presidential candidates, particularly the group seeking to become the conservative alternative to Texas Gov. George W. Bush, the front-runner for the nomination. Buchanan finished third in the straw poll four years ago.

Pat Choate, the Reform Party's vice presidential nominee in 1996, said last night he has been trying to persuade Buchanan to seek the Reform Party nomination. "So far it's unrequited love," he said.

Choate said he believes Buchanan would be "a great candidate" for the Reform Party and said the party's nominating process would be more open than it was in the past. "Our problem is convincing him to do it."

A decision by Buchanan to seek the presidency as a third-party candidate could complicate Republican efforts to recapture the White House in 2000 by draining away conservative votes from the GOP ticket.

Earlier this summer, New Hampshire Sen. Robert C. Smith quit the GOP presidential race and the Republican Party, complaining that the party has abandoned its conservative principles. He held out the prospect of running for president as a third-party candidate.