Donald Trump has closed the gap on Joe Biden in the race for the White House, a new poll for CNN has shown.

Coming ahead of the party conventions, the poll showed 50 per cent of registered voters were backing Biden and his proposed vice president Kamala Harris.

While 46 per cent said they would vote for Trump and vice president Mike Pence.

And the gap is even closer across the 15 battleground states as Biden polls at 49 per cent, while Trump has 48 per cent.

This is in stark contrast to polls back in June. One, conducted by the Washington Post and ABC showed Biden had a ten point lead over Trump. The Democrat had 53 per cent of the vote, with Trump back on 43 per cent.

A big positive for Biden, it seems, is that he is not Trump, with 29 per cent of voters saying they would vote for Biden as a way to get Trump out of the White House.

Overall, 54 per cent of people polled disapproved of Trump while 42 per cent approved, and while his disapproval rating is lower than it has been this year, it lands him at the lower end of historical approval ratings of past presidents seeking re-election.

Barack Obama polled at 48 per cent, George W. Bush had 49 per cent, Bill Clinton showed 53 per cent and Ronald Reagan tops the chart at 54 per cent.

Biden will officially accept his nomination to be president at the Democrat convention today. The event, which will run until Thursday, will be slightly different than usual as it will be hosted virtually due to the pandemic.

While the Republican party convention will be held from August 24 to 27.