Angry Democrats have spoken out over President Joe Biden pardoning his son Hunter when he had previously pledged to stay out of legal proceedings.

Democrat Governor Jared Polis was among the first to criticise the decision that has lit a political firestorm, with condemnation from both sides.

“While as a father I certainly understand President @JoeBiden’s natural desire to help his son by pardoning him, I am disappointed that he put his family ahead of the country,” Polis posted to X.

“This is a bad precedent that could be abused by later Presidents and will sadly tarnish his reputation.

“When you become President, your role is Pater familias of the nation.

“Hunter brought the legal trouble he faced on himself, and one can sympathise with his struggles while also acknowledging that no one is above the law, not a President and not a President’s son.”

Dr Jill Biden was asked by press during a holiday event at the White House whether she supported her husband’s decision.

The First Lady responded by backing her stepson’s pardon.

“Of course I support the pardon of my son,” she said.

A Democratic representative from Arizona, Greg Stanton, said Biden had “got it wrong on this one”.

“This wasn’t a politically motivated prosecution. Hunter committed felonies, and was convicted by a jury of his peers,” Stanton wrote on X.

Biden announced on Monday (AEDT) he had made the decision to pardon Hunter Biden, who had pleaded guilty to tax violations and was convicted on firearms-related charges.

“Today, I signed a pardon for my son Hunter. From the day I took office, I said I would not interfere with the Justice Department’s decision making, and I kept my word even as I have watched my son being selectively, and unfairly, prosecuted,” the president said.

The White House had said repeatedly that Biden would not pardon or commute sentences for Hunter, a recovering drug addict who became a target of Republicans, including President-elect Donald Trump.

“No reasonable person who looks at the facts of Hunter’s cases can reach any other conclusion than Hunter was singled out only because he is my son,” Biden said in a statement released on Sunday before leaving for a trip to Africa.

The grant of clemency said Biden had granted “a full and unconditional” pardon to Hunter Biden for any offences in a window from January 1, 2014, to December 1, 2024.

Hunter Biden faced sentencing for the false statements and gun convictions in November.

In September he pleaded guilty to federal charges of failing to pay $US1.4 million ($2.2 million) in taxes while spending lavishly on drugs, sex workers and luxury items.

He was scheduled for sentencing in that case on December 16.

“I have admitted and taken responsibility for my mistakes during the darkest days of my addiction — mistakes that have been exploited to publicly humiliate and shame me and my family for political sport,” Hunter Biden said in a statement on Sunday, adding he had remained sober for more than five years.

“In the throes of addiction, I squandered many opportunities and advantages … I will never take the clemency I have been given today for granted and will devote the life I have rebuilt to helping those who are still sick and suffering.”

Trump slams ‘abuse of justice’

Republicans criticised the president’s move.

“Does the Pardon given by Joe to Hunter include the J-6 Hostages, who have now been imprisoned for years? Such an abuse and miscarriage of Justice!” Trump said in a post on his Truth Social site, referring to those convicted for storming the US Capitol on January 6, 2021, after Trump claimed falsely that he had won the 2020 election.

“Joe Biden has lied from start to finish about his family’s corrupt influence-peddling activities,” said Representative James Comer, chair of the House committee on oversight and accountability.

The president, whose son Beau died of brain cancer in 2015, said his opponents had sought to break Hunter with selective prosecution.

He said people were almost never brought to trial for felony charges for how they filled out a gun form, and said others who were late in paying taxes because of addiction but paid them back with interest and penalties, as his son had, typically received non-criminal resolutions to their cases.

“It is clear that Hunter was treated differently. The charges in his cases came about only after several of my political opponents in Congress instigated them to attack me and oppose my election,” Biden said.

“In trying to break Hunter, they’ve tried to break me — and there’s no reason to believe it will stop here. Enough is enough.”

-with AAP