Dominion Voting Systems has filed a defamation lawsuit against Rudy Giuliani, Donald Trump’s lawyer and former New York City mayor, seeking $1.3bn for his alleged role in perpetuating the “big lie” about fraud in the 2020 election.

The legal claim against Mr Giuliani is part of a broader effort by the voting machines systems company to push back against the debunked accusations from Mr Trump and his allies, which have turned it into a target for criticism and disdain among the former president’s supporters.

The lawsuit was filed on Monday in federal court in the District of Columbia, following a similar claim lodged by Dominion against Sidney Powell, the rightwing lawyer who brought post-election litigation on behalf of Mr Trump.

“[Mr Giuliani] and his allies manufactured and disseminated the ‘Big Lie’ which foreseeably went viral and deceived millions of people into believing that Dominion had stolen their votes and fixed the election,” the lawsuit said.

John Poulos, Dominion’s chief executive, alleged Mr Giuliani had “incessantly repeated the false claims about Dominion voting systems on a range of media platforms”.

Mr Giuliani could not be reached for comment by phone and did not immediately respond to a request for comment sent to his consulting firm.

In the final months of his presidency, Mr Trump launched a sustained effort to overturn the results of November’s election as he sought to cling to his office, culminating in the deadly assault by his supporters on the US Capitol.

As he did so, Mr Trump reportedly received help from Jeffrey Clark, formerly acting head of the US Department of Justice’s civil division. The New York Times reported this weekend that Mr Clark had worked with Mr Trump to try to replace the acting attorney-general and call the election results into question.

The inspector-general at the DoJ announced on Monday it was investigating whether current or former members of the department had been involved in trying to use their office to overturn the election results. The DoJ declined to comment.

Dominion, meanwhile, is taking its own action against Mr Trump’s allies and their campaign to overturn Joe Biden’s victory, saying it was seriously damaged as a result.

“Dominion has been unfairly subjected to the hatred, contempt, and distrust of tens of millions of American voters, and the elected officials who are Dominion’s actual and potential customers have received emails, letters, and calls from their constituents demanding that they avoid contracting with Dominion or using Dominion machines,” it wrote in the lawsuit against Mr Giuliani.

The company has also promised to bring legal action against others who have repeated those claims about its role in last year’s election, and said it has not ruled out suing Mr Trump himself.

“We’re looking at everybody, and what role they played in either making statements themselves about Dominion, or perpetuating the false statements that were made,” said Tom Clare, the company’s lawyer. “So, at this stage, we have not ruled anyone out.”

Mr Clare said another potential target for legal action could be Mike Lindell, the chief executive of pillow company MyPillow and a close ally of Mr Trump.

Mr Lindell was one of several people to receive a letter in December from the company warning him to stop repeating his false allegations about the company. Last week Mr Lindell told CBS News: “I want them to sue me. Please.”