US President Joe Biden has said that the Democrats has secured a "historic" framework for a vast social spending plan, signaling he expected the deal to be passed by lawmakers.

"I know we have a historic economic framework," Mr Biden said in an address to the nation after discussing the package with leaders of his party, which has been divided on the cost and details of the initiative.

"It is a framework that will create millions of jobs, grow the economy, invest in our nation and our people, turn the climate crisis into an opportunity and put us on a path not only to compete, but to win the economic competition for the 21st century," he said.

Mr Biden failed in his original goal of securing a vote in Congress, where Democrats hold a razor-thin majority, before going to Rome for meetings with Pope Francis and G20 leaders, then a UN climate summit in Glasgow.

Instead, his dramatic last-minute intervention will present Democrats with a deal too good to refuse, senior aides believe.

"This framework also makes the most significant investment to deal with the climate crisis ever -- beyond any other advanced nation in the world," Mr Biden added on a day of frenzied activity aimed at securing support for the $1.75 trillion plan.