Kamala Harris has achieved another first after she held the power of US president for one hour and 25 minutes while Joe Biden was anaesthetised for a routine colonoscopy.

At her inauguration in January, Ms Harris became the nation’s first female, first Black and first South Asian vice president.

Now she has become the first woman to hold US presidential duties, albeit for 85 minutes.

She worked as acting president from her office in the West Wing while Mr Biden underwent the procedure.

Afterwards, Mr Biden resumed his duties at about 11.35am and was “in good spirits”.

“He will remain at Walter Reed as he completes the rest of his routine physical,” tweeted White House press secretary Jen Psaki.

.@POTUS spoke with @VP and @WHCOS at approximately 11:35am this morning. @POTUS was in good spirits and at that time resumed his duties. He will remain at Walter Reed as he completes the rest of his routine physical.

— Karine Jean-Pierre (@PressSec) November 19, 2021

Mr Biden was admitted to the national military medical centre for his first routine physical exam as president which was announced in a morning tweet.

“As was the case when president George W Bush had the same procedure in 2002 and 2007, and following the process set out in the Constitution, President Biden will transfer power to the Vice President for the brief period of time when he is under aesthesia,” Ms Psaki wrote.

“The Vice President will work from her office in the West Wing during this time.”

Pursuant to the 25th Amendment to the Constitution, Mr Biden sent a letter to House Speaker Nancy Pelosi and Democratic Senator Patrick Leahy of Vermont, the president pro tempore of the Senate, saying he was unable to discharge his duties while under aesthesia.

“Today I will undergo a routine medical procedure requiring sedation. In view of present circumstances, I have determined to transfer temporarily the powers and duties of the office of President of the United States to the Vice President during the brief period of the procedure and recovery,” stated the letter.

Afterwards, a letter was sent back returning power to the president.

Mr Biden, 78, is the oldest person to serve as US president, and interest in his health has been high since he declared his candidacy for the White House in 2019.

He had his last full exam in December 2019, when doctors found the former vice president to be “healthy, vigorous” and “fit to successfully execute the duties of the presidency,” according to a doctor’s report at the time.

Dr Kevin O’Connor, who has been Mr Biden’s primary care physician since 2009, wrote in a three-page note that the then-presidential candidate was in overall good shape.

-with AAP