Around 1.6 million pet owners have had their cat or dog put down during the past five years because they could not afford to pay for their medical treatment, a survey has showed.

Around 6% of owners said they had their pet put to sleep during the period because they could not afford the vet's fees, while 10% had declined the recommended treatment for a condition for the same reason, according to Sainsbury's Finance.

The group estimates that 927,000 dogs and 822,000 cats have been put down for this reason during the past five years.

The findings are supported by research carried out among vets, with 51% saying they had been asked to put down a cat or dog during the period because their owner could not afford to treat them.

Around 80% of vets also said they had seen owners decline a course of treatment for their pet because of the cost involved.

The group said one of the main reasons for the problem was that advances in veterinary medicine meant the cost of vets' fees were rising by around 12% a year.

At the same time around 55% of cats and dogs are not insured, leaving their owners to pick up the full bill for the cost of their treatment.

Neal Devine, Sainsbury's pet insurance manager, said: "Our findings are very disturbing but also frustrating because in many cases if the owners had taken out good quality pet insurance they would have been able to treat their pet without any problems.

"The current credit crunch could compound this situation even further, with as many as one million pet owners looking to reduce their pet insurance cover or do away with it all together."