Amritpal Singh, 25, said he was woken about 4am on Friday by noises inside his Onehunga house, before a man burst into his room with a knife.
"They were already getting the stuff out and scaring my friends," he said. "They came in my room and they cut my head with the knife, near the right eye."
Singh said he and his three flatmates were told to lie on the ground in their rooms by one or possibly two armed men.
"They are saying, 'Who wants to be killed first? Who wants to die first? I'll kill you'."
Singh said the intruders also threatened to cut one of his ears off. Meanwhile, two women stole their possessions. None of the intruders had their faces covered but they were not known to anyone in the flat.
The intruders also had a sadistic side. At one point, Singh said, they took milk out of the fridge and poured it over the flatmates while they were lying on the ground.
"I don't know why they are doing this," he said.
The intruders worked quickly and thoroughly, stealing laptops, mobile phones, wallets, clothes, shoes, and car keys from the house - but not the flatmates' cars. They ransacked all but one of the rooms in the house.
"Everything," Singh said. "They cleaned [out] the house properly. Because they spent 40 minutes in the house."
A police spokesperson said they received a call about an aggravated burglary around 5.30am on Friday, and confirmed that one person suffered a small facial laceration during the incident.
Three people - two women and a man - had gained entry to the house and there was possibly a fourth person waiting in a car nearby, police said.
The offenders had not yet been identified or located and police said anyone who saw anything suspicious in the area at the time should report it.
About 9.30am, Singh's credit card was used at a Caltex petrol station, which the police were investigating.
Singh went to hospital where he received two stitches for the cut beside his eye. He also suffered a blackened eye. No one else was injured in the incident, but they were rattled after the prolonged attack.
The flatmates stayed at a friend's place on Friday night because they were too afraid to stay in the same house. They were now looking to move to a new flat.
"They said to us, 'We will come back soon'," Singh said.
The break-in follows reports of people knocking on Auckland residents' doors in the early hours of the morning. Several people reported a woman who appeared distressed asking to be let in to their homes on the North Shore.
In the Onehunga case, it was not known how the intruders entered the house.
THREE DAYS OF VIOLENCE • Friday, 3.30am: Home invasion in Onehunga, 1 injured. • Saturday, 1.40am: 31 year-old man seriously injured in shooting at a bar in Manukau. • Saturday, 9.20pm: Man dies after being assaulted in Otahuhu. • Sunday, 1.45am: Man injured in shooting on Cross St, near K Road.