The Trump administration is mulling a new plan to secure funding for the border wall by reallocating existing federal money.

The move would allow Trump to secure the funds without declaring a national emergency, and without triggering another government shutdown.

White House chief of staff Mick Mulvaney told NBC's "Meet the Press" on Sunday that the move is "entirely legal" because there are "pots of money" that presidents have access to.

Critics of the plan disagree, and say the move would likely draw just as much blowback from Congress and the courts as a national emergency declaration would.

President Donald Trump has been eyeing a move that could secure more funding for his border wall without resorting to declaring a national emergency — and it could allow him to save face to accept a deal in Congress that grants him just a fraction of the funding he has demanded.

Trump has demanded $5.7 billion for the wall, but just weeks after the longest government shutdown in US history, congressional negotiators have indicated they're only prepared to grant $1.375 billion.

So the White House's new tentative plan is to use an executive order to shift unspent federal dollars from areas like disaster-relief projects, flood-control initiatives, and military housing, Politico reported on Tuesday.

One White House official also told The Washington Post on Wednesday morning that Trump views Congress' deal as the only way to stave off another government shutdown, and is likely to sign it and then issue the executive order to reallocate existing funds.

Read more: Trump's staunchest allies are already bashing the 'garbage' bipartisan border deal that could stave off another government shutdown

The acting White House chief of staff called it 'the most likely outcome'

In this Jan. 2, 2019, file photo White House chief of staff Mick Mulvaney listens as President Donald Trump speaks during a cabinet meeting at the White House in Washington. Associated Press/Evan Vucci

Acting White House chief of staff Mick Mulvaney discussed the outlines of the plan on NBC's "Meet the Press" on Sunday, arguing that it was "the most likely outcome.

He said Trump's other options were dismal: he could shoot down Congress' offer and trigger another government shutdown, or accept the small sum that Congress is prepared to provide.

Mulvaney argued that every president has access to "certain sums of money" without resorting to a national emergency declaration, and the trick was in identifying where to get the funds.

"What we're looking at doing with President Trump is stuff that is entirely legal, stuff that is laid out in law already," Mulvaney told host Chuck Todd. "So you comb through the law at the president's request … and there's pots of money where presidents, all presidents, have access to without a national emergency."

Though Trump has said in recent months he'd be open to declaring a national emergency should Congress fail to provide the $5.7 billion he has demanded, he has reportedly come under increasing pressure from some Republicans and top advisers not to do so.

Read more: Here's what would happen if Trump declared a national emergency to build his border wall

In this March 5, 2018, photo, construction continues on a new, taller version of the border structure in Calexico, Calif. Associated Press/Gregory Bull

Simply shifting the military and disaster-relief funds would appear to be the next-best option, but some critics have argued that the new plan could be even more susceptible to court challenges than a national emergency declaration — and could incur even more political blowback.

"It will create a firestorm, once you start taking money that congressmen think is in their districts," Jim Dyer, a former staff director for the House Appropriations Committee, told Politico. "You will cause yourself a problem if that money was directed away from any type of project or activity because I guarantee it has some constituency on Capitol Hill."

The House and Senate are expected to vote on the funding deal by the end of the week. Funding runs out Friday at midnight, and the government will shut down again if Trump doesn't sign the bill Congress passes.