A disclaimer on the show warns viewers the methods can be dangerous and dog owners should seek help from professionals.
"I know someone who attempted to use the technique of blocking her dog and she got bitten," Marett said.
"There is a disclaimer on this programme but people don't watch that. They do what they see. They do it by copying and learning."
SPCA chief executive Christine Kalin said the society did not agree with the trainer's methods.
"We have had a number of people contact us regarding concerns about the programme. However, as we have not seen any actual evidence that suggests a breach of the Animal Welfare Act, we are unable to actively intervene."
Veterinary Association resource manager Wayne Ricketts was concerned the dogs were not muzzled while being trained in public.
"There is a potential risk to other dogs and their owners and it is distracting for the dog who is being trained," he said.
TVNZ publicity manager Katherine Klouwens confirmed there had been "a handful" of formal complaints.
Voglar did not want to comment.
The current season of Last Chance Dogs ends on June 21 and a decision has not yet been made on a further season.
chloe.johnson@hos.co.nz