Dog owners have been warned to "stay vigilant" for their pets trying to eat discarded face masks, with some having been rushed to clinics for emergency surgery.
The coronavirus pandemic has seen a massive uptake in the use of disposable masks, but vets and charities are seeing cases of dogs mistaking them for food or toys and needing emergency surgery to avoid fatal consequences.
When Mike Glanton, from Bristol, saw his border collie Colin swallow a disposable mask, he immediately panicked.
Luckily, he was able to get his pet to Zetland Vets in the city in time, but he described the emergency treatment as "absolutely terrifying".
"People face fines for littering, but there should be more severe penalties for dropping masks during a pandemic," he said.
"They are a massive risk and I would warn other pet owners to keep their wits about them with this new kind of litter. These are the new plastic straws and they put animals' lives in danger."
Julie Veidman's cocker spaniel Ralph needed emergency surgery from vet charity PDSA to remove a disposable mask after he tried to eat it.
The mask had blocked his intestines, which would have been fatal for the dog had she not noticed him refusing treats and taken him to a vet.
"It worries me as you see masks discarded all over the place right now, and Ralph is living proof that dogs might eat them and suffer serious consequences," she said.
The RSPCA has reported over 900 incidents of animals caught in litter since the start of the first lockdown in the spring, although this includes other types of rubbish besides masks, such as cans and plastic bags.
In July, a gull had to be rescued in Essex after it was spotted with a face mask tangled around its feet.
Chris Sherwood, the RSPCA's chief executive, believes the UK will see a rise in similar cases.
"Our RSPCA officers have had to rescue animals from getting tangled in face masks and we expect that this may go up as time goes on," he said.
"Now that face masks are the norm and may be for some time to come, this message is more important than ever as thousands of these masks are being thrown away every day."
He added the charity is now concerned discarded face masks could become a "significant hazard".
Vets have said pet owners should contact their local surgery "without delay" if they believe their animal companion has eaten a face mask.
British Veterinary Association senior vice president Daniella Dos Santos said: "Discarded face masks can pose a serious health hazard for our pets if ingested.
"They can lead to gastrointestinal blockages or internal injuries that require prompt veterinary treatment and potentially life-saving surgery to treat."
Bill Lambert, head of health and welfare at the Kennel Club, says pet owners should keep an eye out for disposable masks or plastic gloves that have not been placed in a bin.
"Dog owners are used to having to keep harmful items such as chocolate and grapes away from their pets, but many may have not yet adapted to the new mask routine, so please do be vigilant and take steps to keep your much-loved pets safe during the pandemic," he said.
The RSPCA has also suggested that people cut the straps off their face masks and cut up disposable gloves before throwing them away to stop animals becoming entangled.
