"I think [President Obama] might consider it," Portman said, "if we make a commitment right now" to tackle tax reform and entitlement reform.

An agreement to extend existing tax rates would give Congress enough time to reach a deal on "pro-growth tax reform" and entitlement reform, he said.

"Which I think can be done in six months," he added. 

"The work's been done by a lot of different groups, there will be increased revenues. Those increased revenues will come from those who are in what is now the top two brackets. And there could be some other revenue."

Many experts say that a partial-year extension of the tax code is a nightmare for taxpayers and the IRS.

Portman added that he was open to a short-term deal on tax reform. 

"I would accept anything that has to do with pro-growth tax reform, one, and, two, entitlement reform," Portman continued. "I'm saying I think we ought to have a deal on taxes."

Portman said he would not sign on to a deal that extended the tax rates for 98 percent of Americans, but put off a tax rate extension for the wealthiest 2 percent of Americans until next the end of 2013. 

Portman said doing that would hurt the economy. 

"The president would get what he wants. He wants to sort of exact his political pound of flesh here after the election. I understand that," Portman said. "But let's not do it in a way that hurts people who are trying to find work. I mean, there's a way to do this, is my point, that deals with tax reform, which as you know is necessary to get this economy moving. It's an antiquated, inefficient system."

Portman's comments came the same day that top congressional leaders met with the president at the White House to begin discussing ways to avoid going over the "fiscal cliff" of automatic spending cuts and tax increases sets to hit in January.