US election: Joe Biden hits Donald Trump where it hurts - in the TV ratings

It's not the tally that really matters, but former VP Joe Biden has scored something of an upset over US President Donald Trump.

In their duelling town halls, the Democratic presidential candidate reached more viewers on ABC than Trump did for NBC News.

The Biden town hall reached 14.1 million people on ABC between 8pm and 9pm, while Trump had 13.5 million combined on NBC, CNBC and MSNBC, the Nielsen company said.

It had been expected that Trump would reach more people simply because it was being seen on three networks.

US President Donald Trump at a campaign rally in Florida on Friday. Photo / Evan Vucci

But with a prime-time lineup of liberal opinion hosts on MSNBC, Trump wasn't particularly welcomed by either viewers or network personnel.

"Well, that just happened," MSNBC host Rachel Maddow said as soon as Trump's sometimes combative town hall with Savannah Guthrie ended, proceeding to launch into a lengthy fact-check.

The Biden town hall, with questions from the audience and moderator George Stephanopoulos, lasted 90 minutes.

NBC had received sharp criticism for scheduling its event at the same time as Biden's.

It was supposed to have been the night of the second debate, but the independent commission cancelled it after Trump baulked at doing a virtual debate.