Pauesi Leofa Brown was threatening Diane Nonu in September 2008 when Mr Hemmings intervened to help her get away. Brown then stabbed Mr Hemmings once in the chest, killing him.
Mr Hemmings has been awarded the Bravery Star, New Zealand's second-highest bravery award, for deliberately putting himself in danger and continuing to protect Ms Nonu until he believed she had reached a place of safety.
"As soon as he confronted the offender, however, it would have become apparent to him that he risked assault and possible serious injury," his citation says.
"This outstandingly brave decision ultimately cost him his life."
Speaking from his home in Matamata, Mr Hemmings' father Richard Hemmings told NZPA he was "quite thrilled" his son's bravery had been recognised.
"Knowing all the aspects of it, it was well deserved. He was that type of guy, he was always sticking his neck out for other people," he said.
Mr Hemmings' mother, Greta, said she was moved by the award.
"We're feeling quite emotional and quite honoured about it. It's a wonderful award and it couldn't go to a more deserving chap," she said.
Mr Hemmings' brother, Cambridge man Craig Hemmings, said the award was a great honour.
"We're proud of Austin of course, we always have been. He left a wonderful legacy as a husband and a father, son, a brother and a friend.
"We're proud of the award, but we'd still prefer to have him here of course," he said.
Craig Hemmings thanked the government and, particularly, the police for their efforts.
"I think Detective Senior Sergeant Gerry Whitley and his team were part of the nomination for this award.
"Austin had quite a strong faith. He always had that in his nature and would always help his fellow man. He would do unto others, which is how he lived his life," he said.
Mr Hemmings' wife, Jenny, and their children, Meghann, 22, Jessica, 19, and Gareth, 18, are expected to accept the award on his behalf.
Brown was jailed last year for life with a minimum non-parole period of 16 years for Mr Hemmings' murder. His appeal was rejected by the Court of Appeal last Friday.
