Democrats intensified their opposition to US President Donald Trump by further delaying the confirmation of several of his Cabinet nominees amid strong Republican objections.

Hours after Trump fired Acting Attorney-General Sally Yates for refusing to defend his executive order banning certain immigrants and refugees, Democrats lashed out during a hearing held to approve his choice to lead the Justice Department.

Amid concerns with information provided by his picks to lead the departments of Health and Human Services and Treasury, Democrats didn't show up at another Senate committee at all.

The theatrics drew more attention to Trump's recent decisions and the growing bipartisan concern with his decision to implement a travel ban with virtually no consultation of top government officials or senior lawmakers.


But it also allowed Republicans to attack Democrats for holding up the formation of Trump's government. Ultimately, Democrats alone lack the votes needed to block any of Trump's nominees from eventually taking office - and there are no signs of Republican opposition to any of his picks.

During a hearing of the Senate Judiciary Committee, Democrats criticised Trump for firing Yates and said that they would not support his nominee for attorney-general, Senator Jeff Sessions because they do not believe he would ever stand up to Trump in a similar fashion.

Just down the hallway of the Dirksen Senate Office Building, the Senate Finance Committee convened to vote on Steven Mnuchin's nomination to serve as Treasury secretary and Congressman Tom Price's nomination to be secretary of Health and Human Services - but Democrats boycotted the meeting, forcing Republicans to reschedule both votes.

Democrats once again tried and failed to stall a vote to advance Trump's pick for Education Secretary, Betsy DeVos, to the full Senate amid fresh revelations that she may have plagiarised some of her answers to written questions from senators. But the panel voted to refer her to the full Senate on a party-line vote.

Amid the rancor elsewhere, two Trump nominees earned bipartisan support in the Senate Energy and Natural Resources Committee. The panel approved the nominations of former Texas governor Rick Perry to be Energy secretary and Congressman Ryan Zinke for Interior and sent them to the full Senate for final up-or-down votes.

Developments in the Finance Committee, however, signalled how defiant Democrats remain in stalling Trump's nominees.

When the meeting began, Finance Committee Chairman Orrin Hatch sat alone at the dais with just three other Republican senators. Having just come from the Judiciary hearing, Hatch told his colleagues, "Jeff Sessions isn't treated much better than these fellas are."

"Some of this is just because they don't like the president," Hatch said, later adding that Democrats "ought to stop posturing and acting like idiots."

Senator Mike Enzi agreed: "I think this is unconscionable."

"We did not inflict this kind of obstructionism on President Obama," added Senator Patrick Toomey the only other senator in the room. He added that the Democrats were committing "a completely unprecedented level of obstruction. This is not what the American people expect of the United States Senate."

But just four years ago, Republicans similarly boycotted a Senate committee's vote on Gina McCarthy to serve as former President Barack Obama's interior secretary. Senators said at the time that she had refused to answer their questions about transparency in the agency.