Foodstuffs South Island is launching a three-month facial recognition trial in three Christchurch stores

The North Island successfully tested the technology last year in 25 stores.

New World St Martins and Pak'n'Save Papanui and Moorhouse are the first South Island stores to take part.

Retail General Manager Tim Donaldson says the trial aims to keep customers and staff safe, noting some individuals continue threatening behaviour even after being trespassed.

He says facial recognition could help identify repeat offenders.

Results will be reviewed before deciding on wider use.