Two prominent Northern Virginia Republicans are bristling over fund-raising letters that Republican Charles G. Viars sent out with their signatures but without their knowledge in his bid to represent Arlington's 49th District in the Virginia House of Delegates.

"I didn't sign it, I didn't know about it and I didn't authorize it," Arlington Commonwealth's Attorney Henry E. Hudson said yesterday. The letters were dated Oct. 16 and 19.

A spokesman for Rep. Frank R. Wolf (R-Va.), whose signature was also on the letters, said the Northern Virginia congressman "did not sign the letter, nor did he give permission for his signature to be used."

Hudson and Wolf have since received apologies from Viars, who is waging an uphill battle to unseat incumbent Del. Warren G. Stambaugh in the 49th District, which encompasses South Arlington.

"I think his stuff speaks for itself," Stambaugh said. "If he'd deceive his own fellow Republicans, who else has he deceived? He's put out literature about me that's full of distortions, so I'm not surprised."

The letters, one addressed to "friends" and the other to 62 political action committee directors, contain almost duplicate texts and attack Stambaugh as being "an extreme liberal" and a "liberal humanist."

"I can't decide if a liberal humanist is worse than a secular humanist or better in the lexicon of the New Right," Stambaugh said.

Viars could not be reached for comment yesterday. But in a letter he sent Hudson yesterday, Viars explained that he assumed it would be all right to use Hudson's signature again because the prosecutor had signed a July fund-raising letter for him. Wolf also signed a similar letter at the time.

"This is not a legal question," Hudson said when asked if laws had been violated. "It's a question of ethics as I view it." He said he also was informing Viars that "I don't wish to have any further part in the campaign."

Wolf's spokesman said he did not know what plans Wolf had in connection with Viars' campaign.

Last month Viars said that Sen. John W. Warner (R-Va.) would speak at a campaign fund raiser for him. A spokesman for Warner said then that the senator would not be campaigning for Viars.