Three dog handlers confronted an offender after tracking a stolen van to the car park of the Mill Street Pak N'Save at about 11.30am this morning, police said.
A sawn-off shotgun went off as they tried to wrestle the man to the ground, seriously injuring the offender and wounding one of the officers.
Neither injury was thought to be life threatening and both the offender and the injured officer were undergoing medical treatment.
Early indications are that the 35-year-old offender is Zeb McCalliion, who was being pursued over a burglary and home invasion in Kihikihi yesterday, police said.
Police commissioner Mike Bush said the three officers had put themselves at risk to protect a member of the public.
"The bravery of these officers in tackling an armed and dangerous offender to keep innocent members of the public from harm is in the finest traditions of the New Zealand Police."
Waikato police commander Bruce Bird said staff were working to support the injured officer's family.
He said it was likely the officer would receive recognition at a later date.
'It turned out to be a shotgun'
Mark Strongman of Huntly said he was shopping with his wife and granddaughter.
He said he saw a van pull into the car park and a man jumped out armed with what Mr Strongman thought was a crowbar.
"It turned out to be a shotgun."
The man tried to force a woman out of her car at the petrol bowser, but was unsuccessful.
"He had a woman by the scruff of her neck and he tried to haul her out. She had the good sense to hang onto the wheel, and not let go."
By this time police had reached the man and Mr Strongman heard a gunshot.
The man was quickly apprehended by at least four police officers, he said.
