WILMINGTON, United States - Newly minted Democratic White House nominee Joe Biden said US President Donald Trump has "cloaked America in darkness for much too long".

The former US vice-president said his rival has unleashed "too much anger, too much fear, too much division".

His impassioned speech was the capstone of a political career spanning nearly half a century.

Mr Biden, 77, heads into the general election campaign with a clear lead in opinion polls over Mr Trump, 74.

But with 75 days to go until the election the Republican president has plenty of time to narrow the gap.

Mr Biden's live speech marked the grand finale of the four-night Democratic party conference.

But there was no balloon drop, cheering throngs, or any of the other fanfare and razzamatazz of the typical American party conference, because of the coronavirus pandemic.

Organisers opted instead for a virtual set piece of mostly pre-recorded speeches crunched into two hours of highly produced programming each evening.

In his address from his hometown of Wilmington, Delaware, Mr Biden said: "Here and now, I give you my word, if you entrust me with the presidency, I will draw on the best of us, not the worst.

"I'll be an ally of the light, not the darkness.

"It's time for us, for we the people, to come together. And make no mistake, united we can and will overcome this season of darkness in America.

"We'll choose hope over fear, facts over fiction, fairness over privilege."

Mr Biden said "character is on the ballot" this November.(FA)