Republican mayoral hopeful Thomas Ognibene reported yesterday that he had raised a little more than $21,000 for his underdog primary challenge to Mayor Bloomberg, a sum that some said was so small as to cast doubt on his chances.

Mr. Ognibene, a former City Council minority leader, filed his fund-raising report with the Campaign Finance Board in time for yesterday’s filing deadline. The documents showed that he had raised $21,384 for his mayoral bid. About $11,485 of that would be eligible to be matched by taxpayers at a ratio of at least four-to-one under the city’s campaign finance program, but only if Mr. Ognibene is able to raise more than $250,000 of matchable funds.

Mr. Ognibene has spent a little over $10,000 so far, the report said.

“This extraordinarily paltry sum shows that he really can’t put up a fight in a Republican primary,” said political consultant George Arzt. “What I wonder about is how many signatures can he raise and will people help him raise that money? He couldn’t make this a viable campaign against the mayor with this kind of money.”

Others are asking whether Mr. Ognibene will get to the September primary at all, given that he needs money to get his message out and be a real threat to Mr. Bloomberg. The mayor has said he will spend whatever it takes (of his own money) to get his re-election message out. The last time out, in the 2001 election, he spent $75 million.

“Ognibene has to raise at the very minimum $250,000 of matchable money to make the race at all competitive,” said a political science professor at Baruch College, Doug Muzzio. “The fact that he hasn’t raised much money just feeds the perception that he isn’t really a contender.”

Mr. Ognibene needs about 7,500 signatures on a ballot petition by this summer in order to qualify for a spot on the Republican ballot. Getting to that figure is especially difficult for GOP hopefuls because there are only 500,000 registered Republicans in the city.

“We expect the big money will come in when we have fund-raisers in April, May, June, and July. Most of the big donors don’t respond to letters. We wanted to get it to the 1,000 matchable donors and we have about 470 now,” Mr. Ognibene told the New York Sun. “The next criteria is getting $250,000 in.”

Mr. Ognibene has been getting political traction by taking advantage of Mr. Bloomberg’s sometimes difficult relationship with rank-and-file Republicans in the city. Some of them are upset with his decision to personally support gay marriage, his property tax hike (an 18.5% increase two years ago), and his penchant for hosting fund-raisers for high-profile local Democrats.

Analysts said the problem is compounded by the fact that in the past three-plus years, Mr. Bloomberg has done little to give Republicans a stake in his re-election. There are few patronage jobs. Mr. Bloomberg has not gone out of his way to allow Republicans to share in the glory of outer-borough projects he has championed. And Mr. Bloomberg’s relations with Republicans in the council have been frosty at best.

The case Mr. Bloomberg has been making behind the scenes with county Republican leaders is that the choice they are making is not between Messrs. Ognibene and Bloomberg, but rather between a Republican mayor who has been good for the city and a Democrat who would not be.

“Ognibene is clearly relishing being the thorn in Mayor Bloomberg’s side,” said political analyst and former councilman Ken Fisher. “But in the end, I think it is more about trying to move the mayor ideologically than anything else.”

In a Republican primary matchup, Mr. Bloomberg is running well ahead of the former councilman, by a 65% to 16% margin, a Quinnipiac poll released earlier this month found. A second GOP challenger, Steven Shaw, an investment banker, is also seeking to run in the Republican primary, and his numbers barely register.

According to the Quinnipiac poll released earlier this month, if the mayoral election were held now, a former Bronx borough president, Fernando Ferrer, a Democrat would win. In a head-to-head matchup with Mr. Bloomberg, Mr. Ferrer beats the incumbent by an eight-point margin.

Last month, the Quinnipiac poll found Mr. Ferrer, who is considered the front-runner among the four Democratic contenders, in a dead heat with Mr. Bloomberg. The Democratic challengers have each raised more than $1 million.

With eight months to go before the election, however, the polls are only an indication of the direction of the race, analysts said. A major problem for the mayor’s campaign prospects is the persistent perception that he doesn’t care about voters’ problems.

Fully 52% of voters in the poll said they do not believe that Mr. Bloomberg understands what troubles them, compared with 41% who said they believe the mayor does care. The Quinnipiac poll involved interviews between February 22 and March 1 with 1,435 people registered to vote in New York City.

The poll numbers like those often bring candidates down to earth. Mr. Arzt said that he always warns his clients to beware of candidate-itis. “Candidate-itis is when someone pats a candidate on the back and they think that actually translates directly to votes. It doesn’t. And in Tom Ognibene’s case, people who say they are glad he’s running aren’t necessarily coming out supporting him.”

Mr. Ognibene said he is “not concerned about the money end of it, I am concerned about the number of volunteers we can get to carry petitions. You have to get 15,000 to come up with the 7,500 uncontested signatures. In 2001, we were able to get 8,000 signatures in Queens County, so I think we’ll make it.” He didn’t say how many signatures he has now.