With still more than two days to go before America votes, bookmaker Paddy Power is paying out to punters who backed President Obama to win the US election.

Despite the national polls showing voters remain largely undecided with nothing more than a sheet of ballot paper between the two candidates, the bookmaker believes it is a done deal and that Obama is a "nailed-on certainty" to win a second term.

President Obama’s election team is mobilising a massive get-out-the-vote effort aimed at carrying the Democrat to victory as the campaign enters its final days.

Meanwhile, Republican Mitt Romney is making a late play for votes in Democratic-leaning Pennsylvania.

Both campaigns predict victory in Tuesday’s election. Obama’s closing out the campaign with an apparent edge in some key battleground states, including Ohio.

Romney’s campaign is projecting momentum and banking on late-breaking voters to propel him to victory in the exceedingly close race.

The Republican will briefly cut away from the nine or so competitive states that have dominated the candidates’ travel itineraries this autumn. Romney, along with running mate Paul Ryan, plan an early evening rally tonight in Morrisville, Pennsylvania