If anyone expected Joe Biden to be celebrating the fact that election rival Donald Trump is now a convicted felon, they were disappointed.

Instead the Democrat's campaign issued a sober warning that the only way to prevent Trump returning to the White House remained the ballot box.

"In New York today, we saw that no one is above the law," Biden campaign communications director Michael Tyler said in a statement, reports AFP. 

"But today's verdict does not change the fact that the American people face a simple reality. There is still only one way to keep Donald Trump out of the Oval Office: at the ballot box."

The White House was even less keen to get its hands dirty after the former occupant of 1600 Pennsylvania Avenue was convicted on all 34 counts in his hush money case.

"We respect the rule of law, and have no additional comment," Ian Sams, White House Counsel's Office spokesperson, said in a curt statement.

From Biden himself there was no comment on Thursday.

The president was at his home in Delaware on what was already a hugely significant day for him -- nine years to the day after his son Beau's death from brain cancer in 2015, aged 46.

Trump's historic conviction -- which would have been a knockout blow in any other election year -- is undoubtedly a brighter spot for Biden after weeks of polling showing him neck and neck nationally with Trump who leads the Democrat narrowly in most of the key swing states.

Biden has previously made occasional jokes about Trump's legal plight, including mocking him for falling asleep at the trial and saying he's been too "busy" to be on the campaign trail.

But he's largely stayed muted on the issue, and the question is now whether he keeps a presidential distance above the fray or opts for a more aggressive approach.

Bd pratidin English/Lutful Hoque