"There's no legislation with regards to abortion that I'm familiar with that would become part of my agenda," he told the Des Moines Register in an interview posted on the newspaper's website.
The former Massachusetts governor said he would instead use an executive order to reinstate the so-called Mexico City policy that bans American aid from funding abortions. President Barack Obama waived the order soon after taking office.
Still unclear is what Romney would do if a Republican-controlled Congress passed abortion legislation and presented it to him to sign into law.
The Romney campaign sought to walk back the comments soon after they were posted on the Register's website. "Gov. Romney would of course support legislation aimed at providing greater protections for life," spokeswoman Andrea Saul said, declining to elaborate.
Romney supported abortion rights when he first became Massachusetts governor, but he changed his position while in office.
Facing skeptical conservatives in the Republican presidential primary earlier in the year, Romney regularly discussed his opposition to gay marriage, abortion and illegal immigration. Once he claimed the Republican presidential nomination, however, he focused almost exclusively on economic issues and has pushed a more moderate tone as Election Day nears.
As both campaigns court female voters, Obama's campaign has featured Romney's opposition to abortion in television ads running in several swing states.
The president's campaign pounced on Tuesday's apparent shift, issuing a statement that "within just a couple hours of the story with Romney's abortion comments posting, his spokesperson clarified that he would in fact support legislation to restrict a woman's right to choose."
"We know the truth about where he stands on a woman's right to choose: He's said he'd be delighted to sign a bill banning all abortions, and called Roe v. Wade `one of the darkest moments in Supreme Court history,' while pledging to appoint Supreme Court justices who will overturn it. Women simply can't trust him," Obama spokeswoman Lis Smith said.
As recently as a presidential debate in January, Romney said the Supreme Court should overturn Roe v. Wade, the landmark ruling that legalized abortion across the nation. He has repeatedly said he would cut federal funding to Planned Parenthood, a women's health organization that provides abortions. Such a move would likely require legislation.
The Planned Parenthood Action Fund says Romney's statement to the Des Moines Register is misleading.
"Mitt Romney's views on women's health are far outside of the mainstream, and that's why he's trying to hide them in the last weeks until the election," said action fund executive vice president Dawn Laguens.
Saul said Romney's position is clear: "Mitt Romney is proudly pro-life, and he will be a pro-life president," she said.