Voter turnout in key battleground states for the US election has reportedly been high, with an increase in early and absentee voting.

Michigan and Pennsylvania are both expected to see high polling numbers, with ballots cast in the two swing states possibly exceeding those cast in 2012.

Absentee ballots cast in Michigan were up 18% on 2012 numbers, while Pennsylvania Secretary of State Pedro Cortes believes he will see around an 80% turnout in the battleground state, The Hill reported.

Around 47 million people cast early ballots in this year's election, with such ballots possibly making an impact in swing states including Florida.

The last election polls released on the morning of the election showed a tight race between the two candidates, while Clinton takes a lead on her GOP counterpart if you include polls released a day before the election.

However, some pundits have predicted a big win for the Democrat, who has several different routes to victory, while Trump needs to win several key swing states in order to reach the White House.

The largest swing state, with 29 Electoral College votes, is Florida, where Trump enjoyed a lead over Clinton in the week before the election.

However, in a dramatic turn of events Florida has dramatically swung towards support for Hillary Clinton in final polling taken on the eve of Election Day.

Most recent polls show Clinton with a nearly 10-point lead to secure the swing state's crucial Electoral College votes. Clinton pushed to 54.9% ahead of 45.1% for Republican Donald Trump in a sharp reversal in Florida from the day before the election (7 November), when Trump was shown to have a 1% lead on Clinton.

Given that the Democrat has held Florida in most polls during the run-up to the election, there is no guarantee that Trump will win the state – putting him at a severe disadvantage if he loses the battleground to Clinton.

A spokesman for his campaign did warn against putting too much emphasis on Florida, however, explaining it would still be possible for Trump to taste victory without the EC votes from Florida.

He said in an interview with CNN: "There are other scenarios. We look at Michigan, we feel very good about today. Colorado, we feel very good, and Pennsylvania we are closing very strongly."