Whirlpool has admitted the number of faulty tumble-dryers in homes across the country could be far higher than first thought, MPs heard on Tuesday.
Executives from the company told the Business, Energy and Industrial Strategy Committee that the true number could be 800,000 and it was working hard to modify those affected.
Last month, the Government said it would issue a recall notice for 500,000 dryers that could potentially be a fire risk.
READ MORE: Whirlpool facing recall notice over tumble dryers
Whirlpool also revealed that in recent years, it had logged 54 fires in its tumble dryers and admitted that three of those were models that had already been updated.
MPs were taking evidence over the scandal that has seen 1.7 million products modified.
One witness Jemma Spurr, a victim whose modified dryer caught fire, told politicians she was asked to sign a non-disclosure agreement about the incident, which MPs said was used for "shutting people up".
She was given an apology by Whirlpool's communications chief Jeff Noel. Turning to Ms Spurr, he said: "I apologise to you for whatever distress this situation has caused to you, to your family, to your loved ones and your neighbours."
Charlie Pugsley, deputy assistant commissioner of the London Fire Brigade, said his teams had seen a wide range of faults causing fires in machines that had already been modified.
And Sue Davies, strategic policy adviser at consumer watchdog Which?, added that a review carried out by the Office for Production Safety and Standards was "completely flawed" because data from Whirlpool had been "incredibly limited".
Whirlpool representatives were asked by Conservative MP Antoinette Sandbach why some victims were asked to sign NDAs, when the company had previously stated it wanted to raise awareness of the problems to encourage customers to register their products.
She said: "Why is it that you are trying to shut people up by asking them to sign NDAs?"
Mr Noel, from Whirlpool, defended their use, saying they are an "important part" of any settlement.
He was asked several times whether Whirlpool will continue using NDAs over the faulty machines, but declined, saying it was a matter for third party insurers.
He was also asked about the Grenfell tower fire, and whether the company stood by its statement that the blaze, which started in a Whirlpool Hotpoint fridge-freezer, may have been caused by a cigarette.
But Mr Noel declined to confirm the company's earlier statement, saying the matter was for the ongoing public inquiry.
He said: "I'm not in a position to say anything other than I think it's appropriate for issues to have been raised - and I don't particularly want to ascertain a statement relative to one item that was made by an individual before a legal body."
Labour MP Vernon Coaker questioned Mr Noel's decision to not answer the question, by suggesting Whirlpool's answers appeared to be "about limiting liability" rather than "helping identify the real cause of a fire".