Mayor Bloomberg won’t have much trouble getting on the ballot as an independent presidential candidate in 2008 if he chooses to mount a campaign, a leading authority on ballot access rules said yesterday.

“As long as he starts early enough, there really is no barrier to him, if he wants to do it,” the editor of Ballot Access News, Richard Winger, said. “New Yorkers always think it’s really tricky because it’s so tricky in New York, but it’s not so tricky in the rest of the country. You need a lot of signatures, but it’s not tied up with teeny weeny technicalities the way it is in New York. “

Mr. Winger said the number of signatures needed to get on the ballot nationwide could be as high as 700,000. A more precise figure will not be known until after elections this fall. Low turnout this year could cause the threshold for 2008 to drop, the access expert said.

Mr. Winger said Mr. Bloomberg would have an easier time getting on the ballot than a Texas businessman, Ross Perot, who captured 19% of the vote in 1992 and 8% in 1996. “Bloomberg does have that big success not only in business, but in government,” Mr. Winger said. “He’s much better positioned than Ross Perot.”

Mr. Winger said one major obstacle to a presidential bid by Mr. Bloomberg is the requirement that candidates score at least 15% in public opinion polls to qualify for televised debates. “The big challenge for him is not ballot access. It’s getting into the debates,” Mr. Winger said.

Discussions about the viability of a Bloomberg presidential campaign have been fueled in recent weeks by the mayor’s regular visits to Washington, his public statements on national issues, and comments by the mayor’s top political aide, Kevin Sheekey.

Over the weekend, Mr. Bloomberg stoked the speculation by discussing his presidential prospects with guests at a fund-raiser for Rep. Christopher Shays, a Republican of Connecticut. According to a report in a Norwalk, Conn., newspaper, the Hour, the mayor said his wealth could fuel a run for the White House, but he also mused about the challenges he would face as a candidate not satisfactory to those at both ends of the political spectrum.

“Running as an independent candidate would be a daunting thing,” Mr. Bloomberg reportedly told guests at the Sunday night dinner. At one point in the evening, he flatly denied interest in the presidency, but he went on to say that any candidate for the office would make such a denial at this stage, the Hour reported.

An unsuccessful independent candidate who drew about 7% of the vote in 1980, John Anderson, said yesterday that he is intrigued by the talk of a Bloomberg presidential bid. “It poses an interesting possibility that he could be the standard bearer for a new body of political thought that wants to get rid of the monolith of the two-party system,” Mr. Anderson told The New York Sun. “It’s going to take really a very dynamic and kinetic kind of candidate to make these arguments and to get these people to listen. Bloomberg is pretty well-spoken and makes a good impression on television. If he really wanted to put his mind to it, I certainly wouldn’t discount the idea.”

Mr. Anderson said Mr. Bloomberg could tap into a “reawakening” of interest in breaking the two-party paradigm in national politics. The former presidential candidate pointed to greater percentages of new voters registering without selecting a political party and to drives in various states and localities to institute so-called instant runoff voting, which can boost independent political hopefuls by allowing citizens to rank candidates in order of preference.

However, Mr. Anderson cautioned that some looking for a truly independent candidate might greet Mr. Bloomberg warily. “His policies have attracted the support of Democrats. He’s probably going to have to gently disengage from the idea that he is simply a Democrat in disguise and that he’s posing as an independent to mask what’s in his heart of hearts,” the former lawmaker and presidential candidate said. “He’s going to have to come up with fresh, creative ideas not now identified as being of Democratic origin or Republican origin.”

Mr. Anderson also said Mr. Bloomberg would have to assure voters he was not on a money-fueled “vanity kick,” as some concluded was the case with Mr. Perot. “He was so idiosyncratic personally and caught up in Ross Perot, period. Bloomberg would have to demonstrate he has a larger vision than just Michael Bloomberg,” the former congressman said.

According to some political analysts, an independent candidate could stand a better chance in 2008 than in prior years because the Internet is eroding some of the advantages of the established political parties. That’s one of the ideas behind a proposal to hold an online political convention, dubbed “Unity ’08,” at which millions of voters would nominate an independent presidential candidate.

A former Republican political consultant who is spurring the effort, Douglas Bailey, said Mr. Bloomberg would be a logical fit for the virtual convention. “If he were to win that competition, he would have something going for him other than his money,” Mr. Bailey said. “It makes his money less of an issue, while still being an extraordinary asset for him.”

Asked what the real-world impact of such a nomination would be, Mr. Bailey said, “The army that puts you onto the ticket is the same army that can put you on the ballot.”

A manager of presidential bids by Ralph Nader in 2000 and 2004, Theresa Amato, warned that Mr. Bloomberg’s wealth would not be sufficient to rebuff attacks from the Democratic and Republican establishment. “We were challenged at every conceivable level in any battleground state,” she said. “Anyone, no matter who they are or how much money they have, will face difficulty being able to get on the ballot as an independent or third-party candidate.”