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The human remains found in suitcases unwittingly bought as part of an auction for abandoned goods in a storage unit in South Auckland are two primary school-aged children.

The Herald yesterday confirmed the remains uncovered at a Manurewa property on August 11 were two young children.

Detective Inspector Tofilau Faamanuia Vaaelua later confirmed the detail in a press conference yesterday afternoon and said initial post-mortem examinations revealed the children were between 5 and 10 years old.

He also said the children had relatives living in New Zealand.

"[Yesterday's] update will be extremely upsetting news for the community to hear," Vaaelua said at the Counties Manukau police station.

"Early indications suggest these children may have been deceased for a number of years before being found last week."

Vaaelua went on to confirm the bodies of the children had likely been stored in the Papatoetoe Safe Store storage facility for three to four years before being discovered.

He said NZ police were also working with the international law enforcement agency Interpol as part of the investigation.

"We've commenced inquiries with overseas agencies. I cannot state any further than that," Vaaelua said.

Scene examinations of both the Moncrieff Ave property where the remains were discovered and the Papatoetoe Safe Store facility have also been completed.

Throughout the press conference, Vaaelua was hesitant to reveal too many details about what police knew of the renters or owners of the storage unit over concerns it may compromise the investigation.

He said police could not yet confirm the genders of the two children.

Earlier this week, a neighbour on the scene at the time of the discovery told the Herald there was "kids stuff in the back of the trailer: prams, toys, walker" that transported the suitcases.

According to police, people living at the Moncrieff Ave house brought "unowned property to their address" last Thursday.

"We reiterate that the occupants of the Moncrieff Avenue property are not connected to their deaths," Vaaelua said yesterday.

"They are understandably distressed by the discovery, and they have asked for privacy. We are ensuring there is support in place for them."

Police at a Manurewa property after human remains were found last week. Photo / Dean Purcell

Police were following "positive lines of inquiry" in terms of the storage unit rental, Vaaelua said, but the formal identification procedures of the remains were "still ongoing" and they were not able to comment on the identities of the children.

Once this is complete, police priority will be to notify the children's next of kin.

"What I can say is we are making very good progress with DNA inquiries," Vaaelua said.

"We want to reassure the community our investigation is continuing to establish the facts to ascertain the full circumstances around the deaths of these children.

"This includes establishing when, where, and how. The nature of this discovery provides some complexities to the investigation."

Vaaelua said the investigation had been difficult for Counties Manukau police officers and detectives but they had a duty to the relatives of the children who were still unaware of the devastating situation.

"I really feel for the families of these victims and right here right now there are relatives that aren't aware that their loved ones have deceased," Vaaelua said.

"As for the investigation team, there are a number of them that are parents. This is no easy investigation and no matter how long or how many years you serve and investigate horrific cases like this it's never an easy task. I myself am a parent of young kids but we have a job to do."

A neighbour told the Herald earlier this week the Moncrieff Ave family found the remains in suitcases while they were unpacking and sorting through a trailer-load of the property on their front yard and driveway.

A man at the property on Tuesday morning said he was looking after the house for his immediate family who had allegedly left Auckland after making the find.

"We're doing all right. As long as everyone leaves us alone we'll be all right," the family member said.

"They've gone away [the family who discovered the remains]. I wasn't here."