The vote is due to take place at 11pm Irish time.
The House has begun a day long debate on the $825bn plan in emergency spending and tax cuts (watch the debate RIGHT NOW at RTÉ.ie/Live).
The US President says he is open to changes to the plan which is one of the most expensive single bills ever considered by Congress.
Most House Republicans were planning to oppose the legislation.
They will offer a competing plan, which is expected to fail, that would scrap the Democrats' hundreds of billions of dollars in spending to jump-start the economy and instead call for a series of tax cuts.
As the debate unfolded in the House, Mr Obama met at the White House with corporate leaders in an attempt to build support for quick passage of an economic stimulus bill that aims to create or save up to 4m jobs.
The bill the House is debating combines $875 billion in temporary tax cuts to spur spending and business investment with hundreds of billions of dollars for job-creating investment projects.
It also contains health industry improvements, expanded aid for the poor and unemployed, and measures aimed at improving education.
Republicans have questioned whether the money actually would support job creation and whether it would be spent over too long a period to be effective.
While President Obama wants a strong bipartisan vote on final passage, that will depend on whether Republicans think they have gotten at least some of what they want, such as more business tax breaks in the bill.
Once the House votes, action moves to the Senate, which is considering a more expensive bill.
Its price tag is now about $887 billion because it will include a one-year fix to insulate middle-class taxpayers from the Alternative Minimum Tax. It was originally aimed at the wealthy, but is affecting a growing number of taxpayers because of inflation.
