US President Donald Trump's campaign attorney has demanded recounts in every state using the software that wrongly gave 6,000 votes to Democrats in one Michigan county.

Jay Sekulow's comments to Fox News on Friday followed revelations that the Dominion Voting Systems vote-tallying machine software that erroneously 'flipped' Antrim County in Michigan from the Republicans was being used in at least 28 states - including the key swing states where the result is being contested.

"If 30 states have used the software that there's already proved to be a glitch of 6,000 votes in one balloting area... lawyers should be... demanding a manual recount," Sekulow said. "post-election litigation is important to protect the integrity of the election process, as the president said, and to protect the constitution frankly."

Those states include Arizona, Georgia, Nevada, Michigan, Minnesota, Nevada and Pennsylvania, all key swing states. Democratic party challenger Joe Biden is leading the count in Arizona, Georgia, Nevada and Pennsylvania by wafer-thin margins of between 7,000 and 35,000.

This week it emerged that the Dominion software crashed voting machines in Georgia's Spalding and Morgan counties crashed for two hours on election day after the company uploaded an update to them the night before.