BILLIONAIRE businessman Donald Trump, who is flirting with a White House run, has lamented that the United States has become a "laughing stock" too timid to wield its power assertively on the world stage.

"We have such power if we knew how to use it," Trump told CNN television in an interview.

He said that by failing to move more decisively in its foreign policy, "this country is a laughing stock throughout the world".

Trump, 64, has not yet announced that he is running for president, but he has become more visible in recent weeks, giving more interviews and stepping us his criticism of President Barack Obama ahead of a possible 2012 challenge.

The wise-cracking, straight-talking real-estate magnate, an early frontrunner among possible Republican presidential contenders, renewed his criticism of Obama as an "ineffective" leader.

He offered the US role in military action against Libya's Muammar Gaddafi as proof of America's new impotence.

"Look at Libya. Look at this mess," an exasperated Trump said.

"We go in, we don't go in, he shouldn't be removed, we don't want to remove him, we don't want to touch him, but he should be removed. Nobody knows what they're doing on Gaddafi.

"I'd do one thing. Either I'd go in and take the oil or I don't go in at all," he said.

"In the old days, when you have a war and you win, that nation is yours."

The billionaire mogul was equally incensed over US policy toward Beijing.

"If you look at what China is doing, they're stealing our jobs, they're taking our money. They're then loaning our money back. It's amazing," Trump said.

"They're making all of our products," he said. "They are also manipulating the currency that makes it almost impossible for our companies to compete with China."

Trump, as much a celebrity in the US as he is a business tycoon, has a massive financial empire that spans everything from beauty contests to prime New York real estate.

Ranked the 420th wealthiest person this year by Forbes magazine with $US2.7 billion ($2.57 billion), the man nicknamed The Donald has said if he runs he is likely to make the announcement on his own hit reality TV show, Celebrity Apprentice.

He insisted he would be a reluctant candidate, despite his recent barrage of interviews.

"I wish I didn't have to do it. I would prefer not doing it. But I love this country," said Trump.

"If you ask me, what are the odds, I'll let you know some time prior to June. But I will tell you, I am giving it serious, serious thought."