Whangarei police are investigating an attempted robbery of a security guard outside the New World supermarket in Onerahi.

Shortly before midday, a security guard collected money from the supermarket and as he walked up to his car, a man punched him and tried to wrestle the cash bag from him.

A member of the public approached, prompting the offender to run off.

Police began a search of the area, calling in a dog and handler, but the offender's yet to be located.

He's described as a Maori in his late teens or early 20s and was wearing a black jumper, black pants, and a grey and blue cap.

The guard has been taken to hospital with concussion and a cut on his face.