Trump's support plummets to new low

Donald Trump (AAP)
Donald Trump (AAP)

Hillary Clinton's lead over Donald Trump has widened to double-digits, new polls have shown.

According to ABC News and the Washington Post, the presumptive Democratic nominee now has a 12-point lead over her Republican rival, 51-39, in a head-to-head match-up.

If the Libertarian and Green candidates are included, Ms Clinton retains her lead, 47-37. Only counting those who say they're "certain" to vote in the November election, Ms Clinton leads by 11.

Nearly two-thirds said Ms Clinton was qualified to be President, while a similar number said Trump was not. Two-thirds said Trump was biased against minorities and 68 percent said he made racist attacks against a judge.

Ms Clinton leads Trump in African-American voters 87-5, Latinos 69-22 and women 52-35. She also leads in urban areas by about 30 points. Trump holds narrower leads amongst white voters, men and independents, and has strong support in rural areas.

Supporters of rival Democratic candidate Bernie Sanders heavily back Ms Clinton, with 78 percent saying they'd vote for her, and 10 percent switching sides and backing Trump.

On Friday a Reuters/Ipsos poll had Ms Clinton winning 46-33.

Another poll by the Wall Street Journal and NBC News also has Ms Clinton in the lead, 46-41. Trump's campaign manager Paul Manafort responded on Twitter, saying he preferred the latter poll.

Trump himself called the ABC/Washington Post poll "dirty" and a "disgrace". He has already banned the prestigious newspaper from covering his rallies.

His campaign has had a rocky few weeks, with reports donors have abandoned him and previous Republican presidential hopeful Mitt Romney saying he'll probably vote for a third party candidate, rather than support Trump.

The President is decided not by popular vote, but the Electoral College -- Trump has an uphill battle there too however, with state polls putting Clinton ahead 334-204, according to poll tracker