Republican lawmakers delivered a stinging rebuke to their leader, House of Representatives Speaker John Boehner, on Thursday when they failed to back an effort designed to extract concessions from President Barack Obama in year-end "fiscal cliff" talks.

The dramatic twist threw into disarray attempts to head off $US600 billion worth of indiscriminate tax hikes and spending cuts that could push the US economy into recession next year.

It also cast doubt over Boehner's future as speaker after failing to control unruly conservatives in his caucus.

With only 11 days left for bickering politicians to prevent automatic tax hikes and spending cuts, US stock futures fell sharply on the news of the rebuke to Boehner.

The Ohio congressman had hoped to demonstrate Republican unity by passing a bill through the House, known as "Plan B," that would limit income-tax increases to the wealthiest sliver of the population - those earning $US1 million and more, a far smaller slice of taxpayers than Obama wants to pay higher taxes.