A violent altercation between two groups at the Z petrol station on East Tamaki Road, Papatoetoe, left two people injured, one critically, according to witnesses.
Police, who were called to the scene around 1:20 p.m., described it as an assault involving a sharp weapon, though no further details were provided.
Both injured individuals were transported to Middlemore Hospital, and police are seeking further information from the public regarding the incident.