The White House has rejected "baseless" allegations of wrongdoing against US President Joe Biden after Republican lawmakers launched an impeachment inquiry against him.

Although the US President is silent when asked by reporters about the probe, his spokeswoman pushed back against the investigation by his political foes.

"They have spent all year investigating the president... and have turned up with no evidence, none, that he did anything wrong," Biden's Press Secretary Karine Jean-Pierre told reporters.

"That's because the president didn't do anything wrong."

"Even House Republicans have said the evidence does not exist," she said. "This is a political stunt."

The probe comes as Biden faces low poll ratings ahead of a likely rematch with former president Donald Trump in next year's presidential election.

Biden ignored impeachment questions from reporters at the White House while leading a meeting of his "Cancer Cabinet" which aims to eradicate the disease, part of a recent effort by the administration to put the focus back on his domestic agenda.

Cancer is personal for Biden, whose eldest son Beau died from brain cancer aged 46 in 2015. Biden had a cancerous skin lesion removed in February while doctors removed two from First Lady Jill Biden a month before.

Biden has stood resolutely by his sole surviving son, Hunter, 53.