Kemi Badenoch has accused Henry Staunton, the former Post Office chairman, of spreading “falsehoods” in order to get “revenge” on her for sacking him.
In a statement to the Commons on Monday, the business secretary hit back at claims made by Staunton in the Sunday Times.
He said a civil servant asked him to delay compensation payments to victims of the Horizon IT scandal to save the government money ahead of the election.
Staunton also said Badenoch told him he was being removed from his job in January because someone had to “take the rap” for the affair.
And he accused her of failing to apologise to him after he first found out he was losing his job from Sky News.
But Badenoch denied all three allegations made by Staunton, who she removed from his job in January.
She said there was “no evidence whatsoever” to back up his claim he had been asked to delay payments.
“The reality is my department has done everything it can to speed up compensation payments to victims,” she said.
The business secretary told MPs Staunton was dismissed not to “take the rap” but because there were “serious concerns about his behaviour”.
“While he was in post a formal investigation was launched into allegations regarding to Mr Staunton’s conduct - this included serious matters such as bullying,” she said.
And she said rather than failing to apologise for the way he found out he had lost his job she had been at “great pains to make my concerns about his conduct private”.
“He has chosen to spread a series of falsehoods, provide made up anecdotes to journalists and leak discussions held in confidence,” she said.
“I would hope most people reading the interview in yesterday’s Sunday Times will see it what it was - a blatant attempt to seek revenge following dismissal.”
Badenoch said a formal record of her phone call with Staunton made by officials - when she told him he was being sacked - would be published.
The Horizon IT scandal saw hundreds of Post Office workers wrongly accused of fraud. More than 4,000 people are in line to receive compensation.
The Post Office prosecuted more than 700 workers for fraud and false accounting based on data from its faulty Fujitsu computer system between 2000 and 2015.
Hundreds received criminal records, and had to do community service, wear electronic tags or serve jail time.