The US government's operations are halted for a second consecutive week, with no deal in sight and thousands of employees without pay.

The US government shutdown entered its second week on Monday, with no sign of a deal between President Donald Trump's Republicans and Democrats to end the crisis.

Democrats are refusing to provide the handful of votes the ruling Republicans need to reopen federal departments unless the two sides can agree on extending expiring health care subsidies.

With the government out of money since Wednesday and grinding to a halt, Senate Democrats looked set to vote against a House-passed temporary funding bill for a fifth time.

The hard line taken by Democrats marks a rare moment of leverage for the opposition party in a period when Trump and his ultra-loyal Republicans control every branch of government -- and Trump himself is accused of seeking to amass authoritarian-like powers.

With funding not renewed, non-critical services are being suspended.

Pay for hundreds of thousands of public sector employees is set to be withheld from Friday, while military personnel could miss their first check on October 15.

And Trump has radically upped the ante by threatening to fire large numbers of government employees, rather than just furlough them, as has been done in every other shutdown over the years.

Republicans are digging in their heels, with House Speaker Mike Johnson telling his members not even to come to Congress unless the Democrats cave.

Democratic House Minority Leader Hakeem Jeffries said that Republicans were the ones stalling any hopes of negotiations.

"Mike Johnson and House Republicans need to get back into town. Do your jobs. Democrats will be present," he told a news conference in New York Sunday.

Johnson -- who was due to address journalists at the US Capitol -- in turn blamed the Democrats' Senate leader Chuck Schumer.

"We need them to turn the lights back on so that everyone can do their work. The House did our work," he told NBC.

- Health care worries -

The Environmental Protection Agency and the Education, Housing, Commerce and Labor departments have been the hardest hit by staff being placed on enforced leave during the shutdown, the New York Times reported.

The Justice, Homeland Security and Veterans Affairs Departments, along with the Treasury and Office of Personnel Management have seen the least effects so far, according to the Times breakdown.

With members of Congress at home and no formal talks taking place in either chamber, a CBS News poll released Sunday showed the public blaming Republicans by a narrow margin for the gridlock.

Democrats say that, if no action is taken, 24 million Americans are set to see their insurance premiums under the Obamacare health insurance scheme double next year, while four million will lose their health care altogether.

Republicans argue the expiring health care subsidies are nothing to do with keeping the government open and can be dealt with separately before the end of the year.

Kevin Hassett, the director of the White House National Economic Council, said Sunday layoffs would begin "if the president decides that the negotiations are absolutely going nowhere."

Trump has already sent a steamroller through government since taking office for his second term in January.

Spearheaded by billionaire Elon Musk's Department of Government Efficiency, 200,000 jobs had already been cut from the federal workforce before the shutdown, according to the nonpartisan, Partnership for Public Service.