Read the excerpts: Biden to address threats to democracy in midterm home stretch
Joe Biden (AFP)

President Joe Biden is to address right-wing threats to democracy on Wednesday as the US midterm election campaign enters its final week with Republicans hammering his administration over the state of the economy.

"An alarming number of Republican officials suggest they will not accept the results of this election," White House Press Secretary Karine Jean-Pierre said.

"(Biden) has been clear -- democracy is under assault and we cannot pretend otherwise," Jean-Pierre said, previewing the president's 7:00 pm (2300 GMT) speech at a hall inside the Union Station transit hub on Capitol Hill.

Read an excerpt of the speech below:

The 79-year-old Biden, in an event at the White House featuring employers and union workers, talked up his administration's creation of infrastructure jobs while acknowledging that "inflation is still hurting people."

"Last year, we signed a historic infrastructure law -- once in a generation investment in roads, bridges, railroads, airports, high speed internet, clean air, clean water," he said.

Democrats, who risk losing control of both chambers of Congress on Tuesday, are being attacked by Republicans on inflation and fears of a looming recession, with the Federal Reserve repeatedly hiking interest rates.

The US central bank delivered another steep interest rate increase on Wednesday, raising the benchmark borrowing rate by 0.75 percentage points -- the fourth straight increase of that size and the sixth hike this year.

The consensus among election watchers is that House Democrats will be swept from power in a Republican red tide, while the party's control of the Senate is hanging by a thread.

The nonpartisan Cook Political Report moved 10 House races toward the Republicans on Tuesday in the solidly Democratic states of New York, New Jersey, Oregon, California and Illinois.

Biden, whose approval rating has been underwater for more than a year, has been relatively inconspicuous on the campaign trail.

But he enters the fray in the home stretch with the address calling out right-wingers who deny his 2020 election victory and stump speeches in Pennsylvania, New Mexico, California and Maryland.

Aside from touting his infrastructure efforts on Wednesday, Biden highlighted moves to curb prescription drug price hikes and lower heating bills.

"Starting in January, we're capping the cost of insulin for seniors on Medicare at $35 a month," Biden tweeted, referring to the US national insurance scheme for people 65 or older.

"That's more money at the end of the month to pay for groceries, to get your car repaired, to put toward holiday shopping for your grandkids."

It is a tricky balancing act for Biden, who also has to acknowledge his own supporters' fears over urban violence, burgeoning anti-Semitism and threats to democracy from election deniers.

A hammer attack that left House Speaker Nancy Pelosi's 82-year-old husband needing surgery has renewed focus in the closing stages on violent political rhetoric used by the far right.

More than half of Americans say the price of gas and consumer goods is the economic issue that worries them the most in a new Quinnipiac University national poll.

But 59 percent of Republicans voiced concerns over the potential for significant voter fraud and 54 percent of Democrats worried about widespread voter suppression.

Democrats have some major legislative victories to tout, but they have been hamstrung since Biden's election win by internecine fights between progressives and moderates.

A huge row sparked by the party's leftist flank calling on Biden to negotiate with President Vladimir Putin over Russia's invasion of Ukraine was the most recent example of Democratic dysfunction.

Before settling on a "kitchen sink" strategy of talking about the cash in voters' pockets, Democrats spent much of the campaign pulling in different directions on the importance of abortion rights, climate change, reproductive freedoms and the war in Ukraine.

But polling consistently shows that voters are more focused on their pocketbooks, and internal divisions left Democrats without a cohesive response to Republican attacks that they have mishandled the economy.

If all of the races in Cook's Republican column go as predicted, the party would need to win just six of the 35 "toss up" races to take the majority. Democrats would need 29.

For the first time since July, FiveThirtyEight's Senate forecast makes Republicans more likely than not to take the upper chamber.