A dairy assistant was jumped from behind, beaten and threatened with a machete held against his throat for "a bit of cash and a few packs of cigarettes" last night.
The owner of the Kingsford Supermarket in Mangere has described finding blood all over the floor when he rushed to the scene.
A man and a woman were working at the shop on Raglan St when four masked men, armed with two machetes, entered the shop at 7.28pm.
The male employee, who is in his 20s, was bagging stock and facing away from the door when the men entered, owner Kamaljit Singh said.
"They took less than 90 seconds - they just came in in a flash and jumped on the boy. He didn't see them coming because he was looking the other way.
The female employee, aged around 30, was behind the counter and was not touched but is "shaken" and may need counselling, he said.
"She's brave - she was back at work today," he said. The shop reopened around lunchtime.
He estimates 10 police cars as well as a dog team were at the scene within minutes, along with a police chopper.
"They were there pretty quick," he said. "They tried their best but they didn't catch the men."
When he arrived, the man was "quite injured", he said. "There was a lot of blood on the floor. He went to hospital and he was released about 3am but he's still in for checkups today."
The victim suffered facial and head injuries as well as bruising to his body, according to police.
They are looking at CCTV footage of the incident and have released stills in the hope that family and friends of the robbers will identify them to police.
Detective Senior Sergeant Albie Alexander of the Counties Manukau Major Crime Team said the incident was an absolutely abhorrent attack which involved an excessive level of violence.
"This is absolutely disgusting behaviour and these individuals should be ashamed of themselves.
"There is a high chance that these offenders are easily identifiable to family and friends and we are asking them to do the right thing and notify police."
The offenders need to be held accountable, he said. "They are a danger to the public and this level of violence is totally unacceptable.
"Our community should be safe to go about their business."
Alexander said police were focused on catching the offenders, and had arrested 68 people for aggravated robberies that had happened since February.
"We hope this sends a clear message to those people who think these types of cowardly crimes are acceptable that they will be held to account and placed before the courts."
The offence carries a sentence of up to 14 years in jail, he said.
Singh, 40, owns the business with his wife, and it has been in the family for more than 30 years. This is the first time they've had any trouble, he said.
But he is aware that robberies are happening more frequently, and attended an April crime prevention march in Manukau which called for more police protection and harsher penalties.
"It's so scary looking at the footage," Singh said. "It's a terrible feeling."
"There's nothing really that shopkeepers can do - it has to be the Government that have to make the punishment a bit harsher.
"The police do their job, they catch the people and nothing happens to them. They get a slap on the hand and that's it, they go and do it again because it's easy."
However police were keeping an open mind and the investigation was in its early stages, the spokeswoman said.
Anyone with information on the robbery can call Counties Manukau's major crime team on 09 261 1300 or contact Crimestoppers anonymously on 0800 555 111.