Biden re-emerges to defend agency from Trump 'hatchet'

Former US president Joe Biden has made his first major speech since leaving the White House in January, defending the social security department as the Trump administration cuts staff and shutters some offices.

Biden's speech in Chicago to disability advocates marked a major re-emergence onto America's political landscape, as President Donald Trump's Department of Government Efficiency, run by tech billionaire Elon Musk, makes massive cuts to the federal workforce.

Biden said the Trump administration has "taken a hatchet" to the agency.

"This new administration has done so much damage and so much destruction," he said, as he called Social Security "more than a government program".

"It's a sacred promise we made as a nation. We know just how much Social Security matters to people's lives."

The Social Security Administration pays out $US1.4 trillion ($A2.2 trillion) in benefits to 73 million elderly and disabled Americans annually. Trump repeatedly pledged during his election campaign not to touch Social Security benefits.

Members of the DOGE team have been inside the agency since February, where leadership has pledged to cut at least 7000 staff and shutter offices, triggering fears of longer lines, longer wait times and benefit disruptions.

In March a federal judge said the Social Security Administration likely violated privacy laws by giving Musk's aides "unbridled access" to the data of millions of Americans inside the agency's networks, and ordered a temporary halt to further record-sharing. The case continues.

"President Trump is absolutely certain about protecting Social Security benefits for law-abiding tax-paying American citizens and seniors who have paid into this program. He will always protect that program," Karoline Leavitt, Trump's press secretary, told reporters before Biden's speech.

Many layoffs or resignations have taken place inside the agency's IT departments, and Biden referred to a recent increase in the number of times the agency's computer systems have crashed.

"People can't sign on to their accounts," Biden said. "Who in the hell do they think they are?" he said of the Trump administration.

Some Democrats had misgivings about Biden's speech, saying it might be better for him not to re-enter the political fray.

Karen Finney, a Democratic strategist, said many Democrats are concerned that Biden's appearance will distract from the political and economic blowback Trump is getting for triggering a trade war with China and imposing tariffs on other countries.

"We are finally beginning to see cracks in the armour in terms of Trump's policies," Finney said. "You don't want to become a lightning rod that distracts from Trump. And it could make it easy for Trump to change the subject to Biden."

Biden, 82, dropped his re-election bid last July after a poor debate performance against Trump. Kamala Harris, his vice president, then lost the November election.