"We'll have to see what happens. I think it's going to be a long process, and it could even go to the convention, which is shocking," Trump said.

The real estate mogul, who toyed with his own presidential run after polls last summer showed him potentially leading the GOP field, was also reluctant to knock former Republican vice presidential candidate Sarah Palin, who said over the weekend that she was not yet convinced of Romney's conservative bona fides. But Trump did rise to Romney's defense, arguing that he had "known him a long time" and believed him to be a true conservative.

"I am convinced, I think he's an excellent guy, and an excellent candidate, and frankly, I think she is a fantastic woman," Trump said. "She's not really convinced about anyone at this moment, not just Mitt, it was really anybody."

But Trump said he was sympathetic to Palin's desire to see the nomination fight continue.

"I think she wants to see it go on, I think she thinks it's a good process, and I understand exactly what she's saying — it is probably a good process," Trump said. "It's certainly a vetting process, these guys are suffering."

Trump also cautioned that despite Romney's rebound wins in the Maine caucuses and the Conservative Political Action Committee straw poll, "it's certainly not a race that's over, and surprising things happens."