The 150kg former heavyweight boxer - and possibly New Zealand's only Maori deaf fighter - beelined for the attacker, who then ran off towards Onerahi Cemetery.
"I walked into this and when the boy turned around and saw me he just took off," Mr Moses said through a sign language interpreter.
"He ran across the road and through the cemetery and was gone.
"Maybe he thought I was too big or too ugly."
Mr Moses, a former bouncer with 10 years experience in Whangarei and Auckland venues, said he wasn't scared to approach the attacker and was ready to restrain him if need be.
"I've seen many fights and arguments and I've often had to restrain people in the past."
The 40-year-old senior security officer for Northern Districts Security was taken to Whangarei Hospital with facial lacerations, concussion and a suspected fractured eye socket, but he discharged himself a short time later.
Police and the owner of Northern Districts Security, JP Dignon, thanked Mr Moses for his actions, with Detective Senior Sergeant Dene Begbie saying he possibly prevented further injury to the security guard and also stopped the robber from getting any cash.
Mr Dignon said he considered his security guard a hero as well as he did a great job.
"He managed to fight off the guy who was attacking him for a while before Mita stepped up. We are very grateful for the action of Mita, but also the security guard," he said.
Mr Dignon said the guard was offered counselling and time off, but chose to get straight back to work on Wednesday.
"He did everything he could on that day. We don't expect our guys to be putting themselves in danger, but he has just been fantastic and apart from a cut and blue eye you wouldn't know anything had happened to him," Mr Dignon said.
"We are a very community-minded company that puts about $100,000 a year into sponsorship in our community, such as Hospice, Age Concern and schools, and it's very pleasing to know that a community member like Mita has stepped in to help us out, that's just wonderful."
Mr Dignon intended to meet up with Mr Moses to pass on the company's gratitude.
But Mr Moses said he doesn't consider himself a hero.
"It's just people looking after people. I just approached this guy and he took off."
Whangarei police are appealing for witnesses to and information about the attempted robbery.
Anybody with information can contact Whangarei police on 09 470 2500, or Crimestoppers anonymously on 0800 555 111.
The security guard was leaving a Whangarei supermarket with the morning's takings when he was attacked from behind, knocked to the ground and punched in the face by a robber, who tried to wrestle the bag of money from him.
