When they leave, Mr Katter takes the sign and writes "not" on it.

He's then shown grinning and blowing the smoke from a cowboy pistol before the camera goes to a wide shot showing the two men lying dead in a paddock.

The video's release comes just days after 50 people were killed in America's worst-ever mass shooting in Orlando, Florida.

The ad has been met with anger on Twitter, but some have praised its boldness.