A Sydney council wants to cap the number of cats non-breeders can own.

Wollondilly councillor Simon Landow wants to create “an equal playing field between dogs and cats”.

“At the moment if a cat is walking along the street, if it's in someone's yard, if it's attacking a bird — basically that cat is able to do that because it's actually illegal for council or the RSPCA to pick these cats up,” he said.

“We need the legislation changed ... so there's actually a notion of a stray cat, because currently there isn't.

“What my proposal seeks is to restrict the numbers of cats someone can have, and [introduce] compulsory de-sexing of cats if you're not a registered breeder.”

He said the Companion Animals Act 2008 should be amended so that cats would be treated more like dogs.

“If your dog is off a leash and roaming by itself, council rangers or the RSPA can actually pick these dogs up, scan the microchip and then fine the owners ... so it's about bringing a quality in line with cats to dogs.”

The Office of Local Government says recent amendments have addressed the overpopulation of cats, including permits for owners of female cats not de-sexed by four months of age, and penalties for pet owners who fail to register their cat.

Wollondilly Council says more is needed to protect native species, which are slaughtered in the millions by cats each year.

The NSW Cat Fanciers Association says the cap would be unfair on responsible pet owners.