The head of the US Federal Reserve faces no risk of losing his job and President Donald Trump is happy with his Treasury secretary, a White House official said.

His comments are an apparent attempt to calm Wall Street nerves frayed by Trump's criticism of the Fed. 

Asked if Fed Chairman Jerome Powell's job was safe, White House economic adviser Kevin Hassett told reporters: "Yes, of course, 100%." 

President Trump blasted the Fed on Monday as the US economy's "only problem," and investors have closely followed reports the president had privately discussed the possibility of firing Powell. 

The US Fed chief took his post early last February after being appointed by Trump and has continued the path of gradual rate hikes started by his predecessor, Janet Yellen. 

Legal experts say it is not clear whether Trump could in fact dismiss Powell. 

Wall Street stocks roared back to life yesterday, shaking off four routs in a row following strong retail sales data and White House reassurances that Fed Chair Jay Powell will not be fired.

The Dow Jones finished 5% higher at 22,878, while the broad-based S&P 500 also surged 5% to end at 2,468 and while the tech-rich Nasdaq Composite index advanced 5.8% to close at 6,554.

US stock prices have plunged in recent weeks on concerns about the economy. The S&P 500 index was on pace for its biggest percentage decline in December since the Great Depression. 

Hassett also said Trump was happy with Treasury Secretary Steven Mnuchin, who in recent days has talked with top US bankers and convened a call with a working group of regulators who aim to keep financial markets running smoothly.

"I am highly confident that the president is very happy with Secretary Mnuchin," Hassett told Fox Business Network.