The Fed chair will tell lawmakers that Omicron increases inflation uncertainty.

Jerome H. Powell, the Federal Reserve chair, will tell lawmakers on Tuesday that inflation is likely to last well into next year and that the new Omicron variant of the coronavirus creates more uncertainty around the economic outlook, according to a copy of his prepared remarks.

The remarks by Mr. Powell, who will testify before the Senate Banking Committee alongside Treasury Secretary Janet Yellen, convey a sense of wariness at a time when price increases are running at their fastest pace in three decades.

“It is difficult to predict the persistence and effects of supply constraints, but it now appears that factors pushing inflation upward will linger well into next year,” Mr. Powell plans to say. “In addition, with the rapid improvement in the labor market, slack is diminishing, and wages are rising at a brisk pace.”

Mr. Powell will also address the new variant, which governments and scientists are racing to assess and contain.

“The recent rise in Covid-19 cases and the emergence of the Omicron variant pose downside risks to employment and economic activity and increased uncertainty for inflation,” Mr. Powell said. “Greater concerns about the virus could reduce people’s willingness to work in person, which would slow progress in the labor market and intensify supply-chain disruptions.”

Much is unknown about the new mutation of the coronavirus, but it represents something Fed officials worry about: The possibility that the pandemic will continue to flare up, shutting down factories, roiling supply lines and keeping the economy out of balance. If that happens, as it did with the Delta variant earlier this summer and fall, it could perpetuate high prices.

Inflation has surged in 2021 as strong consumer demand has crashed into the barrier of limited supply. Production line closures, port pileups and part shortages have kept goods from getting onto shelves and to customers, prompting companies to charge more. At the same time, a dearth of labor in certain industries caused by virus wariness and pandemic-related child-care shortages has been pushing up wages and prices for some services.

It’s too early to know if the new virus strain will contribute to those trends, making inflation last longer than it otherwise would. But the new mutation strikes at a delicate moment for monetary policy.

Central bankers are slowing their bond-purchase program, a move that should give them more flexibility to raise interest rates — their more traditional and powerful tool for stoking the economy — if doing so should prove necessary next year.

Several Fed officials have signaled that they may speed up their so-called bond-buying “taper” given how high and how stubborn inflation is proving. Many economists think officials could announce a plan to do so at their meeting in December.

But if the coronavirus again hits the economy, it could make such a decision — and the timing and pace of eventual rate increases — more challenging.

That’s because the Fed balances two goals, controlling inflation and stoking employment, when it sets its policy. A faster and fuller removal of help for the economy might slow down price gains by weighing down demand, but it would likely slow business expansions and hiring in the process.

“We will use our tools both to support the economy and a strong labor market and to prevent higher inflation from becoming entrenched,” Mr. Powell plans to say, after once again acknowledging that the Fed realizes “high inflation imposes significant burdens, especially on those less able to meet the higher costs of essentials like food, housing, and transportation.”

Mr. Powell, whom President Biden plans to reappoint for a second term as Fed chair, will tell lawmakers that the Fed is “committed to our price-stability goal.”