A suspected assault in Pt Chev last night has been downgraded to a medical event, police say.

A St John spokeswoman said last night the ambulance service had taken one person to hospital following an assault.

TVNZ reported that emergency services were alerted to an unconscious man near Great North Rd at 9.44pm.

A police spokesperson told TVNZ that Magnum Motors car yard on Great North Rd had been cordoned off.