After months of Washington gridlock, Congress is set to vote on a $US900 billion ($A1.2 trillion) pandemic relief package, finally delivering long-sought payments to businesses and individuals.

The package is also expected to confirm resources to vaccinate a nation confronting a frightening surge in COVID-19 cases and deaths.

Officials tacked on thousands of pages of other end-of-session business in a burst of legislation as Capitol Hill is set to close down for the year.

The relief package, agreed to on Sunday and finally released in bill form on Monday afternoon, remained on track for votes in Congress on Monday.

The 5,593-page legislation – the longest bill in memory and probably ever – came together Sunday after months of battling, posturing and post-election negotiating.

President-elect Joe Biden was eager for a deal to deliver long-awaited help to suffering people and a boost to the economy and praised the bipartisan spirit that produced the measure, which he called “just the beginning”.

Treasury Secretary Steven Mnuchin, a key negotiator, said on CNBC on Monday morning that direct payments would begin arriving in bank accounts next week.

The final agreement would be the largest spending measure yet. It combined $US900 billion ($A1.2 trillion) for COVID-19 relief with a $US1.4 trillion ($A1.8 trillion) government-wide funding plan and lots of other unrelated measures on taxes, health, infrastructure and education.

The final bill bears ample resemblance to a $US1 trillion ($A1.3 trillion) summertime package put together by Senate Republican leaders, which failed to excite many GOP senators.

As talks stalled, Republicans pulled back to a smaller, $US500 billion ($A658 billion) position that omitted direct payments, supplemental unemployment benefits and food aid, among other priorities.

On direct payments, the bill provides $US600 ($A790) to individuals making up to $US75,000 ($A98,749) per year, with payments phased out for higher incomes.

An additional $US600 ($A790) payment will be made per dependent child, similar to the last round of relief payments in the spring.

The $US300 ($A395) per week bonus jobless benefit was half the supplemental federal unemployment benefit provided under the $US1.8 billion ($A2.4 billion) CARES Act in March and would be limited to 11 weeks instead of 16 weeks.

The direct $US600 ($A790) stimulus payment was also half the March payment, subject to the same income limits in which an individual’s payment phases out after $US75,000 ($A98,749).

Additional details include $US25 billion ($A33 billion) in rental assistance, $US15 billion ($A20 billion) for theatres and other live venues, $US82 billion ($A108 billion) for schools, colleges and universities, and $US10 billion ($A13 billion) for child care.

Democrats failed in a months-long battle to deliver direct fiscal relief to states and local governments, but they successfully pressed for $US22 billion ($A29 billion) to help with COVID-19-related health expenses like testing and vaccines.