Jon Huntsman, who served as ambassador to China prior to his presidential bid, was blunt when expressing his disapproval of how Mitt Romney would handle relations with China. Huntsman said Romney was "wrong-headed."

That's unusual language considering Huntsman endorsed Romney's bid for president last month.

In an interview Thursday, Huntsman was asked by MSNBC's Andrea Mitchell about whether Romney's approach to dealing with China is wrong.

"Well, let's just say that it's not unusual for candidates to be saying certain things about China," Huntsman said. "I've seen a lot of candidates who later became president who used a lot of rhetoric. It's much easier to talk about China in terms of the fear factor than the opportunity factor. I would disagree with some of what Governor Romney has said and it's not surprising that Republicans disagree with each other from time to time."

Huntsman attempted to clarify his support for Romney by saying he bears the best credentials to reinvigorate the economy but continued to stress the difference in opinion he holds regarding U.S.-China relations.

"You're going to disagree on issues from time to time. I happen to think that on the economy he's best placed to do what needs to be done in terms of economic development and the creation of jobs," Huntsman said.

"When it comes to China, I think it's wrong-headed when you talk about slapping a tariff on day one. That pushes aside the reality, the complexity of the relationship, you sit down at the table with somebody like Xi Jinping, and you say we've got North Korea. We've got Iran. We've got Pakistan, We've got Burma. We've got the South China Sea. We have trade and investment, and they all kind of interrelate one with another when you sit down and negotiate a deal. That's just the way the U.S.-China relationship is and has been for 40 years."

Huntsman's disagreement with Romney over China came on the same day that Romney penned an op-ed for the Wall Street Journal which slammed the Obama administration's policy towards China. Huntsman served as ambassador to China under President Obama.

Huntsman endorsed Romney when he dropped out of the presidential race, but Huntsman has yet to appear at any of Romney's events or campaign on behalf of the candidate.

China's Vice President Xi Jingping is currently on a tour through the U.S., making a visit to Washington, D.C. earlier this week and traveled to Iowa on Thursday.

But while Huntsman voiced his disagreement with Romney over China policy, there's one candidate who considers Romney's stance on China to be a key selling point: Donald Trump. "He's the one person who speaks strongly about China because China is ripping this country like nobody is ripping this country," Trump told reporters when he endorsed Romney earlier this month.

 ABC News' Emily Friedman contributed to this report.