The Trump administration is pushing back against claims from former FBI Director James Comey and Democratic Sen. Elizabeth Warren that federal workers will feel the government-shutdown crunch in the form of missed paychecks during Christmas week.

According to official instructions the White House issued last week, government employees will be at risk of delayed paychecks on January 11, if the shutdown isn't ended by then.

But Comey claimed Sunday that employees of his old agency and their families 'will spend Christmas without a paycheck' because of the partial shutdown that began Friday at midnight.

Warren tweeted that affected workers 'will go without a paycheck over the holidays.'

Russ Vought, the deputy director of the White House's Office of Management and Budget criticized Warren's 'inaccurate' claim: 'Federal employees will receive their next paycheck, even under a lapse.'

Former FBI Director James Comey inaccurately claimed this weekend that workers at his old agency will go without paychecks over Christmas because of the partial government shutdown

'FBI families will spend Christmas without a paycheck, said Comey, a reliable opponent of President Donald Trump

Massachusetts Democratic Sen. Elizabeth Warren made the same claim, ignoring that federal workers won't see their paychecks affected until January 11

Warren claimed on Twitter the an 'avoidable' shutdown means 'hundreds of thousands of federal employees will go without a paycheck over the holidays'

The deputy director of the White House office that instructs federal agencies what to do in the event of a shutdown fired back, saying federal employees will still be paid this coming Friday

Comey has stood as an uncompromising opponent of President Donald Trump since his firing in May 2017, and began using Twitter this year to express his outrage at what he sees as a presidency being run off the rails.

'FBI families will spend Christmas without a paycheck,' he tweeted. 'This president promised Mexico would pay for the wall but innocent people are now paying the price for another lie. Our thoughts are with hardworking public servants and their families.'

Trump initiated a longstanding feud with Warren during his presidential campaign, mocking her as 'Pocahontas' for her decades-long claim that she is part American Indian. Warren acknowledged this month that she is not 'a person of color.'

The battle between the two is expected to heat up if Warren enters the Democratic Party's presidential primary race in 2019.

Dan Pfieffer, a former senior aid to President Barack Obama who now co-hosts the 'Pod Save America' podcast, tweeted that news media have written few stories 'about the government workers who won't get a paycheck over the holidays.'

The most visible government closures this week include national parks like the Joshua Tree National Park. It was was open but its visitors center and other facilities were closed

The White House's official shutdown guidance specifies that pay scheduled for December 28 and the days immediately following will be 'issued at the normal time'

The federal government's pay calendar calls for checks on December 28 for work done between December 9 and December 22

Civilian federal employees are paid every two weeks for work ending a week or more earlier.

The last full pay period of 2018 ended Saturday, and Congress had already budgeted for that money. Workers at the FBI and other agencies will be paid as usual, despite the shutdown, beginning on Friday, December 28.

OMB sent guidance to all federal Cabinet agencies last week, including the Justice Department.

'Saturday, December 22, is the last day of the December 9-22 biweekly pay period. ... Paychecks for that pay period should be issued at the normal time (generally, in the December 28 to January 3 time range),' it read.

One exception the White House agency spelled out applies to a small number of employees who worked on Satutrday, the day the shutdown began. That day's work won't be reflected in their pay until the government is reopened at full strength.

If federal employees are denied paychecks in mid-January, they will be repaid what the federal treasury owes them as soon as the shuttered segments of the government are re-opened.

Donald Trump (pictured) cancelled his own plans to travel to Mar-a-Lago for Christmas as the government readied for a shutdown; unlike the independently wealthy president, most federal workers will feel the bite of missing paychecks if the shutdown lasts to January 11

It's unclear how long the stalemate between the White House and Senate Democrats might last.

President Donald Trump is holding out for billions of dollars in funding to fulfill his campaign promise to build a wall between the U.S. and Mexico.

Democrats will take over the House of Representatives on January 3. The impasse could last well into the month if it isn't resolved by then.

Mick Mulvaney, the acting White House chief of staff who ran OMB until two weeks ago, said Sunday: 'I don't think things are going to move very quickly here the next couple of days.'

'It's very possible that the shutdown will go beyond the 28th and into the new Congress,' he said on the Fox News Sunday program.

The shutdown affects about 25 per cent of the federal budget covering nine agencies: the Departments of Agriculture, Commerce, Homeland Security, Housing and Urban Development, Interior, Justice, State, Transportation and Treasury.

Congress exempted itself this year by voting to fund its own operations until the fall of 2019.