"Sidney Powell is practising law on her own," Trump campaign lawyers Rudy Giuliani and Jenna Ellis said in a statement on Sunday.

"She is not a member of the Trump legal team. She is also not a lawyer for the president in his personal capacity."

The announcement came a day after a judge dismissed the campaign's lawsuit seeking to halt President-elect Joe Biden's victory in Pennsylvania, dealing a major blow to Trump's flailing efforts to overturn his November 3 election loss.

Trump had referred to Powell as one of his lawyers in a November 14 tweet.

Powell drew criticism and ridicule last week when she claimed without providing evidence that electronic voting systems had switched millions of ballots to favour Biden.

Powell had made other dramatic claims without evidence, saying she had a voter fraud case of "biblical" proportions in Georgia.

On Saturday, she told conservative Newsmax TV that "Georgia is probably going to be the first state I'm gonna blow up", and accused Republican Governor Brian Kemp of conspiring against Trump.

Powell is currently representing Trump's former national security adviser Michael Flynn in his long-running criminal case.

Democrats and some Republicans accuse Trump of trying to undermine faith in the American electoral system by promoting false claims of widespread voter fraud.

Australian Associated Press