A new poll has revealed that Democratic presidential nominee Joe Biden's national lead against US President Donald Trump has narrowed to four points with just 12 days remaining for the November 3 election.

the new Hill-HarrisX national poll revealed that 46 per cent of the registered voters have said they would vote for Biden on election day, a 1 percentage drop from the same survey conducted earlier this month, reports The Hill news website.

Meanwhile, Trump has the backing of 42 per cent of the voters.

Three per cent of voters said they would vote for someone else and another three per cent they would not cast their ballots at all.

There were 6 per cent unsure voters, a 1 percentage point plunge from the last poll.

According to the RealClearPolitics average of polls, Biden was ahead of Trump by 8.5 percentage points.

On Thursday night, Trump and Biden faced off in the last presidential debate before the election.

The debate featured issued like the Covid-19 pandemic, race relations, inequality, economy, the President's tax filings and Biden's family deals, which have been the major areas of focus this campaign season.