An attorney disciplinary committee said in its motion to suspend Giuliani's licence that there was "uncontroverted evidence" that Giuliani had made false statements to the courts, the public and lawmakers as he pushed theories that the election was stolen through fraud.

"This country is being torn apart by continued attacks on the legitimacy of the 2020 election and of our current president, Joseph R Biden," the committee wrote.

"The hallmark of our democracy is predicated on free and fair elections. False statements intended to foment a loss of confidence in our elections and resulting loss of confidence in government generally damage the proper functioning of a free society."

The ruling on Thursday will prevent the former mayor from representing clients as a lawyer.

Giuliani's lawyers said in a statement that it was "unprecedented" for Giuliani to be suspended before "being afforded a hearing on the issues that are alleged".

"We believe that once the issues are fully explored at a hearing Mr Giuliani will be reinstated as a valued member of the legal profession that he has served so well in his many capacities for so many years," lawyers Barry Kamins and John Leventhal wrote.

In the decision, the committee wrote that Giuliani "communicated demonstrably false and misleading statements to courts, lawmakers and the public at large" as a lawyer for Trump.

Giuliani had claimed the investigation into his conduct violated his First Amendment right of free speech and that he did not knowingly make false statements, according to the decision.

The court rejected those arguments, noting that in Pennsylvania, Giuliani failed to "provide a scintilla of evidence for any of the varying and wildly inconsistent numbers of dead people he factually represented voted in Philadelphia during the 2020 presidential election".

Australian Associated Press