US President Joe Biden and one of his top aides have warned that a federal government shutdown could cause widespread suffering, including the rapid loss of food subsidies for nearly seven million low-income women and children.

Biden said the failure of Congress to fund the federal government would have dire consequences for the African-American community, including cuts to food subsidies, inspections of hazardous waste sites and enforcement of fair housing laws.

He said he and the Speaker of the U.S. House of Representatives, Republican Kevin McCarthy, had agreed months ago on spending levels for the government.

"We agreed, we shook hands. "Now a small group of extreme Republicans in the House of Representatives don't want to follow through on that deal, and everyone in America could face paying the price for that," Biden said.