Police are investigating a ramraid on an Auckland jewellers after a group of offenders using hammers and tyre irons swarmed the store at closing time

A stolen Toyota Aqua reversed into Partridge Jewellers underneath Newmarket's Westfield Mall shortly before nine last night.

The staff locked themselves in a back room, while six masked offenders smashed cabinets and stole a large quantity of high-end pieces of jewellery.

Nobody was injured.

Police found their car abandoned a short distance away with some of the stolen goods inside.

Forensic examinations of the car and store are continuing.