An investigation is being launched into an aggravated robbery in Hillcrest, Hamilton this morning.

Senior Sergeant Charles Burgess says it happened at about 5am.

"The owner of the Hillcrest Minimart in Cambridge Road arrived at his shop and as he opened the front door he was confronted by three men.

"One of the men hit the shopkeeper with a hammer while his associates stole tobacco products from the store.

"The victim sustained head injuries in the attack, including a significant eye injury, and was transported to Waikato Hospital via ambulance.

"Police, including a dog unit, responded immediately and soon established the offenders had left in a vehicle from a nearby car park on Cambridge Road.

"Police are keen to talk to anyone who was in the Cambridge Road area around 5am this morning and may have seen this group of three men.

"If you have any information which might help us to locate the perpetrators of this violent attack on an innocent shopkeeper, please ring Hamilton Police on 07 858 6200.

"You can also provide information anonymously by calling Crimestoppers on 0800 555 111."

A scene examination is being carried out at the shop today and Police are ensuring the victim is supported.