Board member Jim Williams denounced the SPCA policy at a meeting at Lake Hawea yesterday.
The "Saving Lives" policy encourages people to euthanase strays only after first considering trapping, neutering and return programmes.
The SPCA distinguishes between "stray, wild or unowned" cats and "feral" cats.
It says the former live around humans and have many of their needs indirectly met by humans, while "feral" cats have none of their needs met by humans.
Mr Williams said the distinction was "a nonsense".
"Neutering still doesn't stop them eating lizards and birds. If they are not a family pet, they should be put down," he said.
Chairwoman Prof Abby Smith suggested it would be less expensive to "knock off" a pest cat than to euthanase it.
"We are very concerned about conservation issues and we want some action to get rid of the creatures. They are nice in the house but bad outdoors," she said.
The Otago Regional Council does not include cats in its regional pest-management strategy, and the strategy will not be reviewed for several years.
The Department of Conservation only has jurisdiction over public conservation land.
The board agreed to write to the regional council, other conservation boards, the New Zealand Conservation Authority and "all and sundry", expressing opposition to the encouragement of non-domestic cats.
