US former Vice President Joe Biden won Hawaii’s Democratic presidential primary.

The Democratic Party had cancelled in-person voting for the primary, which was originally scheduled to be held on April 4, and conducted the process by a vote-by-mail system due to the coronavirus pandemic, according to the media report.

Biden, who is the presumptive Democratic nominee for the upcoming election in November, secured 63 per cent of the votes while Vermont Senator Bernie Sanders, the progressive candidate who quit the party race and was now backing the former Vice President, obtained 37 per cent, according to the Interim Democratic Party Chair Kate Stanley.

The deadline for returning the mail-ballot was Friday, the Democratic party had said in a statement late March confirming the cancellation of on-site voting.

“Third round ballots should arrive in homes on or about May 2, 2020. The mail-ballot return deadline is May 22, 2020. Results will be tabulated and released on May 23, 2020,” the party had said.

Biden made a controversial remark on Friday when he said during an interview that African-Americans who consider voting for the current president Donald Trump over him in the November election “ain’t black”.

He apologized for his comment hours later when the controversy had already erupted saying that he “shouldn’t have been so cavalier”.

“I know the comments have come off like I was taking the African vote for granted. But nothing could be further from the truth,” Biden said during a phone call with the US Black Chamber of Commerce.

The Democratic National Committee earlier has postponed the party’s presidential nominating convention in Milwaukee, Wisconsin, to August 17, the week before the Republican Party’s convention, scheduled for August 24 to 27 in Charlotte, North Carolina.

Earlier, Trump’s re-election campaign said in a statement that Biden has “had to adopt most of Bernie’s agenda” — policies that Trump has branded socialist.

But in a series of polls conducted last moth, Biden leads Trump in head-to-head general election matchups by an average of 5.9 percent, according to the RealClearPolitics website.

The 2020 US presidential election is scheduled for Tuesday, November 3.