Desexing of dogs and cats is set to become compulsory in South Australia, but the change will not be retrospective.

It will apply for new pets and there will be exemptions for breeders and working dogs on farms.

The South Australian Government said the change was based on the findings of a citizens' jury which urged that more effort be made to reduce the number of animals put down annually.

Estimates are that about 10,000 animals a year are euthanased.

Compulsory desexing has support from the RSPCA, the Animal Welfare League and the state's Dog and Cat Management Board.

Jill Bottrall from the RSPCA said the plan for tighter regulations had been a long time coming.

"I would say that it now has fairly widespread support within the Parliament and so I'm very much hoping, when we see the legislation and go through it we're pretty hopeful that it will get broad brush support through the Parliament," she said.

Environment Minister Ian Hunter said precise penalties for any failure to comply were yet to be decided.

"There certainly will be fines incorporated in the act, but that's something we'll have to work through with our stakeholders about what the reasonable level of fines will be," he said.

"But our major focus will be on education — that seems to return the best value for us is educating the community on how to be a responsible pet owner."