Greyhound ban bites NSW Libs: Joyce

A backlash against Liberals in NSW local government elections was a "cathartic mechanism" to deal with anger at a ban on greyhound racing, Barnaby Joyce believes.

The federal Nationals leader said there would be much analysis of the political lesson from Saturday's vote but to him it was simple.

"Be careful of your core constituency - they bite," he told ABC TV on Sunday.

Labor claimed large swings towards it in the western Sydney local government areas of Liverpool, Penrith, the Blue Mountains, Blacktown, Campbelltown and Camden, while independent Clover Moore was re-elected as Sydney mayor for a fourth term in the face of a challenge from the Liberals' Christine Forster.

Mr Joyce believed the western suburbs results reflected a reaction to the Baird government's decision to ban greyhound racing.

"I just think that the greyhound decision has not been accepted in many areas," he said.

"It's probably good that the local government election is out of the way; it's a cathartic mechanism to deal with it in some form."