From 1 July 2019, people selling or giving away cats or dogs will need to include an identification number in all advertisements.
The identification number can be either a microchip number, a breeder identification number or a rehoming organisation number.
The changes will provide potential pet owners with more information to make informed choices about the dogs or cats they are buying.
Potential pet owners can visit the NSW Pet Registry to find out information about an advertised animal including its breed, age, gender and whether it is de-sexed. They will be able to look up information about the animal's history, the breeder and seller.
Minister for Agriculture Adam Marshall said the government is protecting the welfare of cats and dogs through this process.
"These new requirements will promote responsible cat and dog breeding and selling by allowing relevant agencies to identify and deal with problem breeders," Mr Marshall said.
