Police have launched an investigation following an aggravated robbery on Heaphy Terrace, Hamilton that left a retail worker injured.

Three men entered the store armed with a machete and making demands, police said in a statement.

One person was assaulted, receiving a wound to the shoulder, and has been taken to hospital in moderate condition.

Police said they were called to the premises around 2pm but the offenders had fled the scene in a vehicle.

Hamilton City Area Commander, Inspector Andrea McBeth, said police are working to identify them and hold them accountable.

"We have received several eye witness accounts as well as footage, all of which will be extremely useful in our investigation.

"While we want to remind people never to put themselves in harm's way, we always encourage witnesses to come forward, and we greatly appreciate the assistance today," McBeth said.

Anyone who witnessed the incident and has not yet come forward is encourged to do so by calling 105 and quoting event number P053535896.