INDIANAPOLIS — The nation's system of public financing for presidential elections is "creaky" and needs to be updated, Sen. Barack Obama said April 11, offering another possible argument for not accepting taxpayer dollars to pay for his presidential campaign.

Obama, who has raised a whopping $234 million from about 1.3 million donors, said the limited amount of money available from the federal treasury for presidential campaigns poses difficult choices for candidates raising large sums.

"I think that it is creaky," he said of the program financed by $3 checkoffs in tax returns. "The amount of money raised through the public financing system may be substantially lower than the amount of money that can be raised over the Internet, which presents candidates then with some pretty tough decisions in terms of how they want to move forward if they want to compete in as many states as possible."

This year, the presidential nominees would be entitled to $84 million in public funds in the general election.

Speaking to donors at a fundraiser earlier last week in Washington, Obama likened his fundraising to a "parallel public-financing system," a remark that set off speculation that if he is the Democratic nominee he would be the first presidential candidate to forego federal funds in three decades.

But on April 11 Obama said he had not made a decision about his general-election money plans and said that if he secured the nomination he would meet with John McCain, the likely Republican nominee, to discuss ways to reduce the influence of outside groups in the election.

McCain is taking steps to accept the public funds, returning money he has raised so far that was designated for the general election. But he said he would reconsider if Obama decides not to accept the public funding.

"I have a record on reform; Senator Obama has rhetoric on reform," McCain said. Speaking to reporters in Dallas, McCain said he would be glad to work with Obama on reform, but "that doesn't change the fact that he committed a year ago to public financing if I would. In direct contradiction to his rhetoric, he's now saying well, he may not do it."

Obama noted that participation in the $3 checkoff had declined, reducing the amount of money in the fund. Obama himself, however, did not check off the $3 designation in his 2005 and 2006 tax returns. Obama, who had checked off the box in previous returns, said it was an oversight. "It may be a situation where my accountant didn't do it," he said. His campaign later said that an amended 2006 tax return did assign the $3 to public financing.

Obama acknowledged that besides an unusually large number of small donors, he also has relied on well-connected fundraisers with corporate interests. But he said his financial operation is separate from his policy positions.

"We have a national finance committee, they are very active but they don't interact with me," he said. "They are not as a general rule part of my day-to-day policy or advisory committee. Although there are some people who have raised money for me who are also prominent business leaders, so if we were putting forward an economic plan and there was some expertise there we would tap into it."