Manufacturer Whirlpool has admitted there is a fault with a range of up to 5.3 million Hotpoint, Indesit and Creda dryers and they should be switched off immediately and the company will offer a free modification.
This comes after fire chiefs warned in October that owners of the faulty dryers must stop using them, after one of the machines was found to be the cause of a huge blaze in a tower block in London.
Whirlpool initially insisted the faulty machines were safe to use so long as they were not left unattended. But they have now backtracked and updated advice on their website after receiving enforcement notices from Trading Standards officials.
Various dryers made between April 2004 and September 2015 are subject to a safety notice about the fire risk, which is caused by excess fluff coming into contact with the heating element.
The Whirlpool website now states: "Trading standards confirmed, following an internal review by independent experts, that the modification programme remains the most effective way of resolving this issue.
"As a result, we will continue with our efforts to provide consumers with a free of charge modification as quickly as possible. The modification programme will continue.
"If your tumble dryer is affected by this issue then you should unplug it and do not use it until the modification has taken place."