NEW YORK — Donald Trump stepped up his contentious search for a secretary of state on Tuesday before he ditches cabinet interviews later this week to lead a victory tour kicking off in the swing state of Ohio.

The billionaire’s nominee for the job will be America’s public face to the rest of the world, the person who will succeed John Kerry, head up a department of 70,000 staff and lead the largest diplomatic operation in the world.

The prospective candidates touted most frequently have been erstwhile Trump critic and former Massachusetts governor Mitt Romney, celebrated general yet scandal-clad former CIA director David Petraeus, Senate Foreign Relations Committee chairman Bob Corker and outspoken former New York mayor Rudy Giuliani.

Aides say Trump is ahead of schedule in unveiling cabinet picks, mostly recently fierce Obamacare critic Congressman and former surgeon Tom Price as health secretary and Elaine Chao as transportation secretary -- both nominated on Tuesday.

But all eyes are on a trio of key posts that remain to be decided: the secretaries of defence, state and treasury -- for which US media reported that Trump was expected to name former Goldman Sachs investment banker Steven Mnuchin as early as Wednesday.

The Wall Street Journal also reported, citing a transition official, that Wilbur Ross, a billionaire investor known for taking over ailing industrial firms and selling them for a big profit, would be named as commerce secretary.

For the top diplomat brief, Trump held talks Tuesday with Senator Corker, considered a safe pick without the baggage of Petraeus and unfettered by Romney’s history of disloyalty to the billionaire.

Corker, 64, said after the meeting that he thought Trump had narrowed the choice "to a very small group of people" and it was important that the president-elect selects somebody on the same wave length.

"This is a decision that he needs to make," the Tennessee senator told reporters. "He needs to choose someone that he’s very comfortable with and he knows that there’s going to be no daylight between him and them."

He said that Trump did not discuss a timeline for announcing his pick. "I think he’ll make the decision when he’s comfortable," said Corker. — AFP