WASHINGTON (AFP) - Treasury Secretary Steven Mnuchin on Friday (March 24) lauded President Donald Trump, saying the 70-year-old in the White House had the hardy good health to excel in his new job.

"He's got perfect genes. He has incredible energy and he's unbelievably healthy," Mnuchin said, during an event organised by the news website Axios.

"This guy has got more stamina than anybody I've ever met. I travel with him all the time. It's unbelievable."

Trump has boasted of his own robust health and Friday's remarks echoed statements made in 2015 by his personal physician Harold Bornstein, who proclaimed in a letter that Trump would be "the healthiest individual ever" to win the presidency.

Bornstein subsequently revealed that he had written the letter in five minutes and told The New York Times that Trump took statins to treat elevated cholesterol, as well as antibiotics to treat rosacea, a common skin condition, and a hair-growth drug.

Mnuchin said Trump no longer dines on McDonald's or fried chicken from fast-food chain KFC because cuisine at the White House is "great."

The official praised Trump for his open-door policy at the Oval Office, making him easily accessible.

"People are coming and going and he thinks about something and calls somebody on the phone," he said. "This is not a formal, scheduled president."

Trump also understands the gravity of his new role, he said.

"He has excellent judgment. I think he understands the seriousness of this job, and the responsibility." Mnuchin also jokingly said Trump's likeness should appear on the US currency.

"I think we should look at putting President Trump on the thousand dollar bill."

The Treasury stopped distributing the US$1,000 bill in 1969.