Clinton regains double-digit lead: US poll

Democratic presidential contender Hillary Clinton has regained a double-digit lead over Republican rival Donald Trump, a Reuters/Ipsos poll suggests.

The June 20-24 poll says 46.6 per cent of likely US voters supported Clinton while 33.3 per cent supported Trump. Another 20.1 per cent said they would support neither candidate.

Trump's slip this week came as he struggled to show that he can keep up with a Clinton campaign apparatus that has dwarfed his in size and funding.

The Reuters/Ipsos poll was conducted online and included interviews with 1201 likely voters in all 50 states. It has a credibility interval, a measure of accuracy, of 3.3 percentage points.