A dog has been shot, a man assaulted with the butt of a rifle and five others left traumatised after a violent home invasion in Mt Roskill overnight.

Two women and four men were playing cards in a Duke St house about 12.45am when five men with their faces covered, and wearing gloves, burst through the front and back doors and threatened them, Auckland police spokeswoman Noreen Hegarty said.

The attackers had three firearms, a hammer and a spade between them. One of the men playing cards was assaulted and hospitalised, however his injuries are not thought to be serious.

A collie dog at the house was also shot, but is expected to live.

The invaders stole thousands of dollars in cash, jewellery and a car from the premises. The car, a black 2003 Toyota Camry saloon with the licence plate FFB616, has not been found.

A woman who lives four doors down from the house, and has lived there for about 50 years, claimed the property was a well-known gambling den.

Mary Magee said a friend of hers, selling calendars for the local church, had visited there late last year "and he took notice of all the money on the table and put two and two together".

The retiree said mainly Thai men would visit the house between Thursday and Sunday and wouldn't leave until around 2am.

"Cars would be parked up on both sides of the street... one weekend a whole mini-van of them turned up," she said.

Detective Sergeant Rick Veacock said although the offenders were wearing gloves and had their faces covered, they had been described by the victims as Maori or Polynesian men.

"I don't believe this was a random act, given the amount of planning the offenders would have done in terms of disguising and arming themselves.

"The fact that these offenders were prepared to discharge a firearm at the dog is very worrying and we need to locate them as soon as possible before anyone else gets hurt."

Hegarty said police were examining the scene and speaking to people in the area. Some of the victims were being interviewed with the assistance of Chinese interpreters.

Not all of the victims lived at the house, but they were all from Auckland.

Officers have asked neighbours to look out for the missing car and for any discarded clothing.

Anyone with information is asked to call Auckland's western area crime line on 027 494 6683 or Crimestoppers anonymously on 0800 555 111.

- © Fairfax NZ News