Police were still on the hunt for the robber, who is described as Maori in his late teens or early 20s. He was wearing a black jumper, black pants and a light coloured grey and blue cap.
Northern Districts Security owner - and the guard's boss - Jean-Pierre Dignon wants to thank the man who immediately came to his aid.
"We can't be grateful enough. It shows the spirit in this town. Because we are such a small community, people don't want to tolerate lowlifes like this. We won't stand for this any more."
Mr Dignon said the guard exited the supermarket and went to open the door of the company vehicle, when he was struck from behind.
He dropped to his knees and was punched in the face.
"His eye socket has been opened. He's okay but a little bit shaken up.
Whangarei police spokeswoman Sarah Kennett said the robber ran away towards Onerahi Primary School.
Police are also thanking the man for his actions, with Detective Senior Sergeant Dene Begbie saying he may have prevented further injury to the security guard and also stopped the robber from getting any cash. Ms Kennett said a police dog handler was called to assist in the search for the man, which included combing the nearby Onerahi Cemetery, but he was still yet to be located.
Police are appealing for information from anyone who witnessed the attempted robbery
In particular, they would like to hear from a woman who passed on some information to another member of the public but did not stay to speak to police, she said.
Anyone with information can contact Detective Constable Jade Henry at Whangarei police on 09 430 4500 or Crimestoppers on 0800 555 111.
