After fervent New Year brinkmanship, the US Congress Tuesday finally backed a deal to avert a "fiscal cliff" of tax hikes and slashing spending cuts that had threatened to unleash economic calamity.

As global stock markets made their 2013 debut, the House of Representatives passed a deal between the White House and Senate Republicans to raise taxes on the rich and put off automatic $109 billion budget cuts for two months.

The deal passed the Senate early on Tuesday, but its fate hung in the balance for hours as House conservatives sought to amend it to include big spending cuts, which would likely have killed it.

In the end, the House voted 257 votes to 167 to pass the original bill with minority Democrats joining a smaller number of majority Republicans to pass the legislation after a bitterly contested and unusual session on New Year's Day.

President Barack Obama planned to make brief remarks at the White House within minutes of passage of the deal, which relieved investors who feared that continued logjam could have sent global stock markets spinning.