Biden also netted the crucial swing state of Michigan and still holds leads in Nevada and Arizona – enough to put him over 270 electoral votes without needing to win Pennsylvania.

Trump’s lead in Georgia is also thinning, with the late counting of mail-in ballots from Atlanta pushing Biden within 50,000 votes of the incumbent.

Counting in Pennsylvania continues, with an estimated 88 per cent of the vote counted so far.

Mail-in ballots from Philadelphia are gradually shrinking Trump’s lead in the state, with some data analysts confident Biden is on track to win Pennsylvania despite the prolonged counting process.

A call in Pennsylvania could come earlier than Nevada, where state officials said they will not start releasing the remaining results until 3:30 am tomorrow (Adelaide time).

Biden currently only holds an 8000 vote lead in the state, although this is expected to grow with mail-in ballots tipped to strongly favour Democrats.

In nearby Arizona, there are 600,000 votes left to count, all of which are mail-in ballots tipped to favour Democrats.

Fox News were the first to call Arizona for Biden followed by Associated Press. Other outlets, such as the New York Times and FiveThirtyEight, have been more hesitant to call the state given the high number of ballots outstanding that were previously unreported.

Wisconsin officials finished their tally at about noon local time after an all-night effort, showing Biden with a lead of just over 20,000 votes, or 0.6 per cent, according to Edison Research.

The Trump campaign immediately said it would seek a recount, which is permitted under state law when the margin is below 1.0 per cent.

The Trump campaign has also filed lawsuits in Michigan, Georgia and Pennsylvania in an effort to contest ballots being counted after election day.

In duelling conference calls with reporters earlier on Wednesday, officials from each campaign insisted their candidate would prevail.

“If we count all legal ballots, we win,” Trump campaign manager Bill Stepien said, potentially setting the stage for post-election litigation over the counting of mail-in ballots.

Biden campaign manager Jennifer O’Malley Dillon told reporters the former vice president was on track to win the election while senior legal adviser Bob Bauer said there were no grounds for Trump to invalidate lawfully cast ballots.

“We’re going to defend this vote, the vote by which Joe Biden has been elected to the presidency,” said Bauer, adding that the campaign’s legal team was prepared for any challenge.

The recent swing of results has prompted the Biden campaign to launch their transition team website “buildbackbetter.com” – a clear sign of the campaign’s growing confidence in the election result.

 – AAP