Whirlpool should offer the owners of more than half a million recalled washing machines the option of a refund alongside a repair or replacement, according to the Which? consumer group.

The US company is launching the UK-wide recall on Thursday after admitting that up to 519,000 appliances sold under its Hotpoint and Indesit brands between October 2014 and February 2018 were a fire risk because they could be affected by a door lock flaw that could lead to overheating.

The company has offered to repair or replace the unsafe machines, but Which? has warned that this could leave a large number of customers with the dangerous appliances in their homes for many months.

Its warning follows earlier research into Whirlpool’s “chaotic” repair or replacement programme for fire-risk tumble dryers that started in 2015. It found that a quarter (26%) of affected customers were told they would have to wait longer than six months for their tumble dryer to be repaired.

The washing machine recall was announced just a week before Christmas when hundreds of thousands of families were told their Hotpoint or Indesit washing machine had a serious safety fault, which to date has caused 79 fires.

Which? has since been contacted by worried Whirlpool customers who are struggling without the use of their washing machine and fear they could be left in limbo for months while waiting for a repair or replacement. Others have bought new machines rather than endure a long wait for a functioning appliance and many have racked up considerable expenses in trips to the launderette.

The consumer group says it is also concerned about conflicting advice from Whirlpool and the government’s product safety regulator about whether or not customers can continue to use the machines at all while they are left to wait for a repair or replacement.

Sue Davies, the head of consumer protection at Which?, said: “It would clearly be unacceptable if customers were left for many months without adequate washing facilities in their homes, particularly when there is also no offer to cover consequential costs such as trips to the laundrette.

“The company should do the right thing and offer customers a refund, so people can get fire-risk machines out of their homes and quickly find a suitable replacement.”

A Whirlpool spokesperson said: “We want to apologise for any inconvenience caused by this recall. The issue relates to a particular combination of components which are no longer used in the production of certain models of Indesit and Hotpoint washing machines.

“Replacing or repairing affected units completely removes the risk of this issue and avoids any possibility of the machines entering the second-hand market. Therefore this is the most effective means of removing this risk from people’s homes.”