Police are investigating the fatal beating of a Christchurch dog at the weekend.

The six-year-old greyhound escaped from its owner's property about 10.30am on Sunday after a gate was accidentally left open.

It was only missing a few minutes when it was found dead 500 metres away in Aldershot St, near Wainoni Park, having suffered "severe blunt force trauma" to its head, said Constable Brian Scanlan, of New Brighton police.

There was no evidence the dog had been hit by a vehicle, he said.

Anyone with information about what might have happened is asked to call police.