Virginia Republican leaders had harsh words yesterday for one of their own--state Sen. Warren E. Barry--for making a last-minute, $45,000 contribution to help his son, a Democrat, unseat the GOP sheriff in Fairfax County.

Republicans accused Barry of betraying the many contributors to his state Senate reelection campaign by funneling some of that money into his son Stan's race for sheriff. Warren Barry is running unopposed Tuesday.

Campaign filings show that the senator has given $75,000 to his son: a $25,000 loan in June, the $45,000 donation last Monday and $5,000 earlier in the campaign.

"Republicans are flat-out steamed," said Fairfax GOP Chairman Joseph P. Underwood. "I've had many of his contributors call me. I find it to be a gross breach of the trust that contributors have placed in Warren Barry."

A senior Republican official said Gov. James S. Gilmore III is furious. Gilmore, who declined to comment, has campaigned hard for Fairfax Sheriff Carl R. Peed, also a Republican, including making an appearance in a TV ad.

"The governor is not pleased. It shows his [Barry's] true colors," said the official, who declined to be named. "Here people are writing checks to reelect Warren Barry, and he is reshuffling this money to defeat a Republican sheriff. If I were a donor, I'd be pretty angry."

Sources said state Republicans are talking privately about stripping Barry, a moderate who often votes with the Democrats, of his chairmanship of the Transportation Committee.

"Frustrations have reached a point where some are questioning his leadership role," one GOP leader said.

Warren Barry dismissed the criticisms. He said he gave the money to his son's campaign because of what he called "slanderous attacks" by Peed in campaign mailings citing Stan Barry's juvenile criminal record.

"I stayed out of this race," the senator said. "But when Peed continued with these attacks, I just felt as a parent I had to do something."

Barry said he has given about $8,000 to other GOP candidates statewide and has held fund-raisers for Republican Senate candidates Daniel F. Rinzel and Whitney Adams, both of Fairfax. Barry said he's had "no indication" that his chairmanship is in jeopardy.

The father-to-son donations are the latest eruptions in a red-hot brawl between Stan Barry and Peed. From the moment Barry, a former sheriff's deputy, announced plans to run against his boss, the campaign has been marked by increasingly negative charges and countercharges.

Even in mailboxes bulging with campaign literature, the dueling sheriff's race brochures--one featuring a Pinocchio-like caricature of Peed and the other a laundry-list chart implying that Stan Barry is a career criminal--manage to stick out from the rest.

After Peed's latest mailing this week, Barry lashed out at his ex-boss, accusing the sheriff of maliciously distorting his background. Barry enlisted the help of his father and Sen. Richard L. Saslaw (D-Fairfax), who held a news conference Thursday to accuse Peed of driving the sheriff's race further into the mud.

"If you're an incumbent you usually don't do this unless some pollster is telling you you've got big problems," said Saslaw, the Senate minority leader.

Peed, who has been sheriff of the Washington area's largest jurisdiction since 1990, did not return several telephone calls yesterday seeking comment.

Warren Barry said his son's misdeeds--including convictions for drunken driving and trespassing and a stolen-auto charge later dismissed--were youthful indiscretions from 20 years ago that Peed has characterized as more serious and recent acts.

"I've been in politics 30 years, and I've never seen a piece this dishonest," the senator said.