Barack Obama has blamed congressional Republicans for US government shutdown, saying the budget stalemate is caused by their "obsession" with obstructing his health-care plan and the influence of the conservative Tea Party.

The president's remarks came during a speech in Washington DC on Thursday after negotiations between him and congressional leaders ended in stalemate.

The partial shutdown of the government - which has led to service closures as almost 800,000 workers are forced to stay home - is now in its third day.

"This whole thing is about one thing, the Republican obsession with the Affordable Care Act. That seems to be the

only thing that unites the Republican Party right now," Obama said.

He called for a straight vote to reopen government but said House of Representatives Republican leaders were intimidated by the most conservative members of their caucus, who were influenced by members of the Tea Party.

Political stalemate

The stalemate began after the law funding government services ran out earlier this week and Republicans in the House tried to tie any new budget law to a curtailment of Obama's healthcare plans.

The Democratic-controlled Senate has rejected the House's attempts.

Obama directly attacked Republican House Speaker John Boehner, saying he could end a "reckless" shutdown in just five minutes.

"Take a vote, stop this farce and end this shutdown right now," he said.

He said Boehner could reopen the government and send hundreds of thousands of people back to work "in just five minutes" by passing a temporary operating budget with no partisan strings attached.

"Speaker John Boehner won't even let the bill get a yes or no vote, because he doesn't want to anger the extremists in his party," Obama said.

"That is what his whole thing is about. "There's a simple way to prove it. Send the bill to the floor, let everybody vote."

"It will pass. Send me the bill, I will sign it. The shutdown will be over and we can get back to the business of governing and helping the American people. It could happen in the next half hour."