Democratic National Committee Treasurer Paul G. Kirk Jr. yesterday moved closer to claiming the panel's chairmanship after winning a key test vote before the committee.

Kirk, a former aide to Sen. Edward M. Kennedy (D-Mass.), easily survived a challenge aimed at unseating 25 at-large committee members. His opponents had said they saw it as their best hope of denying him a victory when the party elects new officers today.

The vote against calling a new election of at-large members this morning was 178.05 to 146.45 and came after impassioned debate and a day of behind-the-scenes lobbying by representatives of candidates for party chairman and by organized labor, strongly represented among the at-large members.

Later, Kirk's opponents said that they might be able to stop his candidacy today and that the vote was not a clear test of Kirk's strength. But other Democrats predicted that his show of strength was sufficient to assure election.

Kirk's challengers include former North Carolina governor Terry Sanford, former California Democratic chairman Nancy Pelosi and Robert J. Keefe, a veteran Washington political operative.

The challenge to at-large members arose earlier this week as part of last-minute maneuvering over the chairmanship in a contest that grew especially heated in recent days. The animosity became public again yesterday when the four candidates addressed the 378-member committee.

In an implicit criticism of Kirk, Pelosi said her election would send a message that the DNC will be led by someone "who is not tied to outdated approaches, who is not identified in the public's mind with one party figure or one party faction."

The battle has divided state delegations, pitted many southerners against fellow Democrats and resulted in hard feelings among the candidates' supporters.

"We have some of the worst name-calling that ever existed," DNC member Fran Bussie of Baton Rouge said at a morning meeting of the southern regional caucus. "Don't play into the hands of the White House. This is just what they want."

Fellow southerners rejected her plea, voting moments later to oust Don Fowler from his long-time position on the DNC executive committee in apparent retaliation for his support of Kirk, rather than Sanford, the southerners' favorite son.

The dispute about at-large delegates occurred because their terms of office expired yesterday.

The rules committee recommended that the 25 be allowed to remain as voting members through this week's meeting, but Kirk's opponents wanted to force new elections in order to produce a new slate less favorable to Kirk's candidacy. Kirk is reported to have a strong majority among at-large members, more than half of whom are labor representatives.

Rules committee chairman Fowler argued that the 25 deserved to remain through the meeting. "We do not change the rules in the middle of the game when we find out who is winning and not winning," he said.

DNC member Joseph Crangle of Buffalo, N.Y., said "fairness" required the party to stick with the at-large members, whom he said "went out and broke their asses" for the party.

Voting against the 25 was voting against "the best damn friends the Democratic Party ever had," he said.

California Assembly Speaker Willie Brown, arguing passionately for a new election, said there "should be equal opportunity for everyone" to be part of the at-large slate.

Outgoing party chairman Charles T. Manatt said he supported a new election but favored reelecting current at-large members.

The DNC also approved resolutions yesterday reducing the power of the party's official special-interest caucuses and affecting composition of the Fairness Commission, which is to review rules affecting nomination of 1988 presidential candidates.

Somewhat lost in the maneuvering was discussion of President Reagan's 49-state election victory over Walter F. Mondale, although several candidates for the chairmanship mentioned it in speeches.

Kirk decried Reagan's ability to take "the buzzwords of traditional values" away from Democrats and invoke Democratic presidents in recalling the nation's great days. "If there isn't a lesson in that for the Democratic Party in 1985, I don't know what is," he said.

Keefe said the party had a "terrible disaster in '84 . . . because we lost touch," not because voters lost touch.

Sanford warned that the party must emerge from this week's meeting united despite the bitterness of the chairmanship fight. "The unity of the party, the success of the party is worth far more to me than winning this office," he said.

Last night, the DNC Black Caucus voted to recommend Richard G. Hatcher, mayor of Gary, Ind., as party vice chairman. He is opposed by Illinois Comptroller Roland W. Burris in a divisive battle. The caucus recommended that the DNC accept its decision.