Emergency services were called to the residential property on Maunu Rd about 6.30pm.
A resident on the street told the New Zealand Herald the scene was swarming with police cars, Armed Offenders Squad officers and police dog teams.
"Police told everyone to lock themselves inside because someone is running around with a knife.
"They said get inside."
Police say they were initially called to a "family harm incident" at the property that was now on fire.
Police confirmed they were searching for an occupant of the house but could not say whether they was armed.
A search has been undertaken of the property and it is believed that all the
occupants of the house have got out safely, a police spokesman said.
"The man involved in the family harm incident is believed to have fled the
scene on foot and Police are currently searching for him," the spokesman said.
Maunu Road is closed between Western Hills Drive and Hospital Road, while
emergency services work at the scene of the fire.
The resident said flames were leaping into the air with "really black smoke" from an old bungalow-style house.
A Fire and Emergency NZ (FENZ) spokesman said crews were in attendance to try to extinguish the blaze.
"The flat fire is 10 metres by 15 metres. No one has been reported missing," the FENZ spokesman said.
