President Joe Biden has completed his course of antiviral pills for Covid-19 and is feeling "well enough" to resume physical exercise as his symptoms dissipate, his official White House doctor said on Tuesday.

Biden, who has isolated at the White House since testing positive for the coronavirus last Thursday, is a keen cyclist and has been reported to start his days with a workout that includes lifting weights.

"The president now feels well enough to resume his physical exercise regimen," his physician Kevin O'Connor said in a memorandum to the White House press secretary.

O'Connor had said on Monday that the president's symptoms had "almost completely" resolved and that assessment was unchanged in the latest health bulletin.

The doctor said Biden had completed his five-day course of the antiviral therapeutic Paxlovid on Monday night.

The president's lungs remain clear and his pulse, blood pressure and respiratory rate are all normal, he said.

Since his diagnosis, the president has been carrying out his full duties, but has observed a lighter schedule.

He told reporters on Monday he was "feeling great" and hoped to be working in person again by the end of this week. (AFP)