WASHINGTON — Lael Brainard, a Federal Reserve governor, said on Tuesday that the U.S. economy remained at risk as the coronavirus pandemic wore on — and support from Congress and the White House would be crucial to cushioning the blow.

“There’s a lot of uncertainty that continues to cloud the outlook; downside risks continue to be important,” Ms. Brainard said at a Brookings Institution event. “It is very important to many households and businesses to have continued fiscal support — just as it was important to them in the early phase of this crisis.”

Her comments came as the future of another government support package remained unclear. Ms. Brainard, who was appointed during the Obama administration, said that monetary policy would also play a key role as pandemic uncertainty persisted, and that central bankers would need to pivot from stabilizing markets to supporting economic growth in the coming months.

“It will be important to provide the requisite accommodation to achieve maximum employment and average inflation of 2 percent over time,” she said.

The Fed unveiled a new long-run policy statement last week, making critical updates to its strategy for achieving its goals of full employment and stable inflation. Ms. Brainard said the tweaks, which together laid the groundwork for long periods of very low interest rates, would help to guide the central bank’s policies coming out of the pandemic.

One key change — the rate-setting Federal Open Market Committee will now aim for 2 percent inflation on average over time, instead of as a more or less absolute goal — will allow for low rates even as prices climb slightly, she said.

“I would expect the committee to accommodate rather than offset inflationary pressures moderately above 2 percent, in a process of opportunistic reflation,” she said.

The Fed’s rework included a major change to the way it views low unemployment. Officials tweaked their long-run strategy statement to say that they would worry about “shortfalls” from full employment, rather than “deviations.” In plain terms, that means that the Fed will no longer raise interest rates simply because joblessness has fallen to low levels.

That’s a big shift from the recent past: The Fed lifted interest rates nine times between 2015 and the end of 2018 partly out of concern that the job market would overheat and spur inflation. Instead, price increases stagnated.

Ms. Brainard said that if the Fed had been using the new strategy several years ago, “it is likely that accommodation would have been withdrawn later, and the gains would have been greater.”

Richard H. Clarida, the Fed’s vice chair and the head of the year-and-a-half review of the Fed’s policy framework that resulted in the updates, also highlighted the central bank’s new approach to full employment during a speech this week.

Low joblessness “will not, under our new framework, be a sufficient trigger for policy action,” Mr. Clarida said, absent pressing financial stability concerns or evidence that inflation is overheating or is likely to run hot.

The Fed’s revised statement emphasized that financial stability concerns will be an important consideration in a world where interest rates are likely to stay low for extended periods, driving investors to make bigger bets in hopes of richer payouts. But Ms. Brainard said monetary policy should not be the primary tool for fighting such bubbles.

Instead, she said, the Fed should use regulation and other forms of oversight to tamp down risks. As part of that tool kit, she said, banks should be retaining their capital — money they can readily tap — to make sure they remain healthy amid the pandemic stress.

“I don’t think they should be paying out dividends,” Ms. Brainard said of commercial banks. “I think they should be hanging onto their buffers.”

The Fed oversees large bank holding companies, and has not yet stopped them from paying dividends to their shareholders. Ms. Brainard objected to that decision.

The Fed has been grappling with slow-burn changes to the United States and global economy. The level of interest rates that the economy can handle without slowing down has fallen, inflation has slipped lower and the relationship between tight labor markets and price gains seems to have broken down. Together, the changes have sapped monetary policy of its strength by leaving officials less room to cut borrowing costs to stimulate growth during downturns.

The Fed announced that it would revisit its policy approach in late 2018 in light of those shifts, and months of conferences and public forums led to the strategy update.

In a panel after Ms. Brainard’s remarks on Tuesday, former Fed officials suggested that the framework Chair Jerome H. Powell detailed last week was a step in the right direction but not a panacea.

“They need to work harder to think about how the different tools coordinate with each other — how they’re going to think about financial stability, how they’re going to add firepower,” said Ben S. Bernanke, who was Fed chair during the 2008 financial crisis. “There’s a lot to be done still. This is just an aspirational, constitutional kind of statement.”

And Janet L. Yellen, who was Mr. Bernanke’s successor, said the central bank could not go it alone as it tried to help the United States to recover from the pandemic-spurred economic crisis.

“In a situation like we’re in now, fiscal policy is necessary and plays an important role,” Ms. Yellen said. “There’s a little bit more the Fed can do — I would look at exploring the tool kit — but I think we also need fiscal policy in a situation like this.”