At a news conference outside the Capitol, Biden said he would testify at a public hearing. But he ignored a subpoena by the House Oversight Committee to testify privately.
The panel has threatened to hold Hunter Biden in contempt of Congress if he did not show.
Republicans in the House of Representatives are pushing ahead with a plan to vote to authorize the probe before leaving for a three-week holiday break on Thursday, even as they leave unaddressed other pressing issues, such as aid to Ukraine and government funding.
They allege that Biden and his family improperly profited from decisions the elder Biden participated in while serving as vice president from 2009-17. Their investigation focuses closely on the business dealings of the younger Biden.
They have so far failed to uncover evidence of wrongdoing by the president.
Hunter Biden, 53, blasted the investigation as baseless.
"There is no evidence to support the allegations that my father was financially involved in my business, because it did not happen," he said.
The White House has denied wrongdoing and dismissed the probe as politically motivated ahead of the 2024 presidential election, in which Republican Donald Trump, the only U.S. president to be impeached twice, is the leading contender to take on Biden. Trump was acquitted by the Senate both times.
Hunter Biden, who has described his struggles with drug and alcohol addiction, has also been subject to a years-long criminal investigation. That has resulted in federal firearms and tax charges.
