Dr Natalie Dumer made the claim in a June 20 YouTube video podcast, which is hosted by Joel Jammal, an Australian political commentator who’s been checked previously by AAP FactCheck.

The video has also been posted on Facebook.

“Why do we need the Dominion machines when they can be hacked, they can be changed…we saw that in 2020,” Dr Dumer says in the video (1 hour 39 minutes 12 seconds).

Dr Dumer did not respond to AAP FactCheck when asked for evidence of her claim. 

Dominion voting machines were used to process presidential ballots in around half of America’s 50 states in 2020.

US-based fact checkers have previously debunked claims that Dominion machines either deleted votes for Mr Trump or switched his votes to Mr Biden.

The claims have also been rebuffed by a group of top US election officials and the Department of Homeland Security's Cybersecurity & Infrastructure Security Agency.

On November 12, 2020, the group issued a joint statement saying there was “no evidence that any voting system deleted or lost votes, changed votes, or was in any way compromised”.

Edward Perez, a US-based voting technology expert and board member at the OSET Institute, a non-partisan non-profit organisation aiming to increase public trust in elections, says the claim has been “thoroughly and repeatedly debunked”.

“Election technology experts and legal authorities have reviewed such claims, and they are not supported by facts,” Mr Perez told AAP FactCheck.

"Sadly, although the claims are baseless, they have nevertheless fueled very real threats of political violence against election administrators and public officials in the US,” he says. 

Dominion Voting Systems has published a web page which challenges false claims made about the company and the 2020 election.

“The US government has confirmed through multiple reports that no vote flipping, voting machine manipulation, or foreign government interference took place in the 2020 elections,” the webpage says.

A Dominion spokeswoman told AAP FactCheck that the claim had been widely debunked by fact-checkers. 

"All independent reviews, including hand counts and audits following the 2020 presidential election, have proven that Dominion voting machines produced accurate results,” the spokeswoman said.

Some counties that used Dominion voting machines on election day 2020 reported minor counting errors, but the glitches were generally found to be caused by human error, not the software.

Mr Jammal told AAP FactCheck that he didn’t agree with Dr Dumer’s claim that Dominion machines had been hacked or switched votes in 2020. 

Former US President Donald Trump has made multiple baseless claims that Dominion voting machines contributed to his 2020 election defeat to Joe Biden, including an unfounded accusation the devices deleted millions of Trump votes.

Trump campaign lawyers Rudy Giuliani and Sidney Powell repeated some of the claims after the election, both of whom were subsequently sued by Dominion Voting Systems for defamation. At the time of writing, these cases are yet to be resolved. 

Dominion also filed a defamation lawsuit against Fox News in March 2021, alleging several programs published false claims about its voting machines. 

In April 2023, the two parties settled just before the case kicked off, with Fox agreeing to pay Dominion $US787 million ($A1.17 billion).

In a statement, Fox said “We acknowledge the court's rulings finding certain claims about Dominion to be false”.