US First Lady Jill Biden will undergo surgery next week to remove a "small lesion" discovered on her face during a routine examination, her spokeswoman said on Wednesday.

The outpatient operation will take place on January 11 at the Walter Reed military hospital near Washington, said White House doctor Kevin O'Connor in a letter made public by the First Lady's spokeswoman Vanessa Valdivia.

"During a routine skin cancer screening, a small lesion was found above the First Lady’s right eye," the letter said. "In an abundance of caution, doctors have recommended that it be removed."

The tissues will be removed and then analyzed, the doctor said.

Jill Biden, 71, is the oldest First Lady in US history, while her 80-year-old husband is also the oldest president in history.

Cancer is a personal cause for Joe Biden, whose son Beau died in 2015 from brain cancer. He has made reducing the death rate from the disease a "presidential priority."