Alvin C. Frost, whose guerrilla tactics and allegations of city contract irregularities caused a furor within the Barry administration, will hold a news conference today, apparently to announce his resignation.

Frost refused to publicly discuss the purpose of the news conference. But another District official, who asked not to be named, said Frost intends to reveal his decision to resign as a senior cash management analyst for the District controller's office and end his career as one of the city's most outspoken employes.

Frost has been a major irritant to District officials for more than a year. He criticized the city's decision to invest with a New Jersey-based government securities firm that went bankrupt, prompting a D.C. City Council probe. He followed up with a Jan. 31 letter to Mayor Marion Barry, alleging "incompetence, mismanagement, negligence, political favoritism, intimidation [and] indifference" in the city's financial management operation.

Frost urged the mayor to suspend Alphonse G. Hill, deputy mayor for finance, and three of Hill's top aides, pending a review of financial management practices.

His conflicts with his superiors came to a head earlier this week when Frost altered the password to the master accounts of the District's financial management system and then claimed he had forgotten it in a public nose-thumbing.

Frost, who has hinted that he may run for mayor, said this week he planned to place clues to the password in the classified section of The Washington Post and offer free trips to the Washington Monument to youths who figured out the word, which he said was drawn from the Declaration of Independence. He also warned that he has programmed the computer to malfunction if attempts are made to retrieve certain information "inserted into the operating system."

District officials hit on the seven-letter password Monday with the help of the firm that sold the computer system to the city. Fred Williams, assistant city treasurer, said late Wednesday that "it took a while, but not much longer than it normally takes to enter a password."

Hill, who denounced Frost as "a nerd and an imbecile" last week, said this week he was through talking about Frost. "It's getting humorous. I have no comment on anything that Mr. Frost does," Hill said.

Frost, whose annual salary is $35,167, was locked out of his office by his superiors during the weekend and was reassigned on Monday with no specific duties.

His most serious allegations have revolved around contracts to handle the city's checking accounts. In his letter to Barry, Frost said Hill ordered that a draft recommendation on who should receive one of the contracts be destroyed. Frost also said the bid accepted by the city was "incomplete and nonresponsive."

Hill called Frost's allegations unfounded and unworthy of comment.