The owner of a Vancouver dog stuck on death row for half its life has lost a bid to appeal the canine's case in Canada's highest court, meaning the dog will soon be euthanized.

The Supreme Court of Canada dismissed Susan Santics's application for leave to appeal Punky the dog's euthanization on Thursday. As usual, the top court did not provide a reason for its decision.

"I'm absolutely gutted. I had hoped we would be able to move forward with this case and bring animal law to the highest court in Canada," animal rights lawyer Victoria Shroff said Thursday.

"This is very, very sad news indeed because it's the end of the road for Punky ... He will be executed."

Punky was ordered destroyed after the dog bit a woman in an off-leash park in Vancouver in 2017. The four-year-old Australian cattle dog has been locked up since, while Santics battled through the courts in an effort to save her pet.

Susan Santics was devastated by the incarceration of her Australian cattle dog, Punky. (Yvette Brend/CBC News)

Three British Columbia courts had already ruled Punky was dangerous, agreeing with a decision from an animal control bylaw officer with the City of Vancouver.

"Given Punky's past behaviour, temperament and lack of rehabilitation prospects ... the dog poses an unacceptable risk to the public and ought to be destroyed," appeal court Justice Patrice Abrioux wrote last year.

In the wake of the top court's decision Thursday, Santics has no legal avenues left to fight the case.

Appeals to the Supreme Court of Canada are not automatic. The court only agrees to hear cases involving significant legal issues of national importance.

Punky was seven weeks old when Susan Santics became his owner. (Susan Santics/Facebook)

Shroff previously told B.C.'s appeal court that Punky's case fit the criteria.

"We are in a transformed legal environment where animals matter," Shroff argued.

"Even if you think an animal is not a family member, before you take somebody's property away — especially sentient property — you'd better be 100 per cent sure that this animal has no prospects of rehabilitation," she said.

On Thursday, Shroff asked the city prosecutor in Vancouver to grant Punky some extra time so Santics could have time to say goodbye. The prosecutor "was understanding," Shroff said, and agreed to give Punky a reprieve until at least next Wednesday.