A charity has warned of increased numbers of abandoned bully XL dogs when they are banned next month.
The change in the law means the dogs owners have to have dogs neutered,microchipped, and exempted, or euthanised.
The Association of Dogs and Cats Homes (ADCH) said vets might struggle to meet demand after the government decided to ban them under the Dangerous Dogs Act 1991 following a rise in fatal attacks.
Owners who choose not to keep their dog must take it to be euthanised by a vet by the end of January and can claim £200 towards the cost.
The ADCH told the BBC it had concerns on how the ban would work, "particularly around veterinary capacity for euthanasia and neutering", as well as vets who refused to euthanise healthy dogs on ethical grounds.
"We fear that these factors will result in a postcode lottery on helping owners euthanise or neuter their bully XLs, and could increase abandonment rates for owners that have nowhere else to turn," the charity said.
The Royal College of Veterinary Surgeons' Code of Professional Conduct says "no veterinary surgeon is obliged to kill a healthy animal unless required to do so under statutory powers as part of their conditions of employment".
From 1 February next year, owning a bully XL dog in England and Wales without an exemption certificate will be a criminal offence, resulting in an unlimited fine and seizure of the dog.
A Department for Environment, Food and Rural Affairs spokesperson said: "We have taken quick and decisive action to protect the public from tragic dog attacks, with the XL Bully type added to the list of dogs prohibited under the Dangerous Dogs Act.
"Up until 31 January 2024, owners of XL Bully type dogs have the options of applying for a Certificate of Exemption or taking their dog to be euthanised by a vet.
"We are working closely with the police, canine and veterinary experts, and animal welfare groups as we take forward these important measures."
