Representative Sean Casten, Democrat of Illinois, is offering pay advances to staffers who would stop receiving paychecks if the government shuts down next weekend.

An intern for Representative Abigail Spanberger, Democrat of Virginia, is compiling a list of food banks and financial resources to display on her website in case her office is shuttered.

And the White House budget office is reminding federal agencies to make plans for a potential shutdown.

With government funding set to expire at the end of next week as the fiscal year closes and with no clear path for a temporary spending measure to keep federal agencies operating, officials across Washington are rushing to make preparations to weather a shutdown that looks more and more likely with each passing hour.

“You have to prepare for the worst-case scenario,” Ms. Spanberger said.

Speaker Kevin McCarthy sent members of Congress home Thursday afternoon after efforts to break a spending impasse with far-right members of his party failed. By the end of the week, lawmakers were in full prep mode and government agencies were dusting off their well-worn instructions for how to function amid the dysfunction.

Some congressional offices, like that of Representative Donald S. Beyer Jr., Democrat of Virginia, were retrieving memos from the last time the government shut down, in 2018, to inform their preparations.

“We had lots of notes from the last time,” Mr. Beyer said in an interview. “We’re trying to figure out how do we get ahead on some of the problems that are going to show up.”

He was one of several lawmakers who were pre-emptively adjusting staff roles to handle constituent services in the event of a shutdown. The casework congressional staffers take on to help with problems that may involve a federal agency, such as passport renewals or addressing an immigration issue, will become much harder to do with many federal workers sidelined.

“Pretty much we’re not going to be able to do anything, because the agencies that we’d be talking to to help us solve it won’t be coming to work,” Mr. Beyer said.

Representative Seth Magaziner, Democrat of Rhode Island, said his staff was prepared to shift roles to handle a higher demand for constituent services, while also focusing on a public campaign to pressure House Republicans, who control the majority, to end a shutdown by cutting a bipartisan deal.

Mr. Magaziner said he would highlight the groups most immediately impacted by a shutdown, such as military families, air traffic controllers and seniors who may not have their Social Security benefits processed during a closure.

“The idea that there are military spouses raising kids while their loved ones are serving overseas, and they’re not going to be getting their paychecks — I mean, I think that there’s going to be a rude awakening for the Republican chaos caucus,” Mr. Magaziner said.

(In a letter last month laying out its contingency plan in case of a shutdown, the Social Security Administration said it would continue paying checks, but discontinue benefit verifications, which are often required for loan applications, housing assistance or other services that require proof of income.)

As in previous shutdowns, members of Congress would continue working with no interruption to their pay, but staff members kept on during the closure would go without pay until new spending legislation were signed into law.

Some lawmakers, recognizing that just one delayed paycheck could spell disaster for many aides, were trying to find ways to soften the blow from the pay disruption.

Representative Steve Womack, Republican of Arkansas, who has been in office for the last three shutdowns, will pay $2,000 advances to staff members in anticipation of a short-term government closure.

“I don’t want any of my staff to miss a paycheck and run the risk of not being able to make rent, because it’s expensive,” Mr. Womack said. “I know the tremendous impact it has on the people least capable of affording it.”

The Congressional Workers Union, which has been organizing around advance pay requests, projects that more than 100 unionized House staffers will receive early pay ranging from $1,500 to $10,000 in preparation for a one to two-month shutdown. This would be the first time a shutdown has taken place since some congressional staff unionized in 2022.

“We still have to make rent, a lot of us are paying for child care, we have to buy groceries. There’s a sense of responsibility to come together and make sure that we’re all going to be OK as we work to reopen the government,” Emma Preston, the union’s president, said.

The Congressional Federal Credit Union, which serves people who work on Capitol Hill, is also offering a zero percent interest loan for 60 days to staffers who are furloughed or working without pay during a shutdown.

But the pain of a shutdown would extend far beyond Capitol Hill. Hundreds of thousands of federal workers across the government are not allowed to work while their agencies remain closed. They would receive back pay when the government reopened because of a law passed after the last shutdown.

Federal courts would be able to operate normally for roughly two weeks without interruption, according to a statement by the Administrative Office of the U.S. Courts, which manages court budgets.

Representatives Gerald E. Connolly of Virginia and Derek Kilmer of Washington, both Democrats, sent a letter to the Office of Management and Budget urging the Biden administration to “take every possible measure” to keep federal day care centers open during a shutdown.

“By ensuring the continued operation of federal child care centers during government shutdowns, we can alleviate a significant burden for federal employees while the work force weathers the challenges that come with any shutdown,” the two lawmakers said in a statement.

Early on, the impact of a shutdown is expected to be felt mostly by the millions of federal employees and contractors who will be out of work. But if history is any guide, the effects could quickly ripple out to the broader public; in 2019, some airport security screeners who were working without pay stopped showing up.

At the White House, officials swatted away detailed talk of contingency planning and said President Biden was focused on urging lawmakers to fund the government and avoid the crisis altogether.

“This is not something we can fix,” said Karine Jean-Pierre, the White House press secretary. “The best plan is to not have a shutdown.”

Erica L. Green and Abbie VanSickle contributed reporting.