A woman who police believe may be the mother of two dead children whose remains were found in suitcases stashed at a South Auckland storage facility could face extradition from South Korea.

The family member is being sought by South Korean police in connection with the discovery of two children's remains earlier this month.

A police officer told Reuters the woman was a Korean-born New Zealander who arrived in South Korea in 2018. There was no record of her departing South Korea since then.

Her whereabouts were unknown and it is unclear whether she had other relatives with her when she arrived in South Korea, Reuters reported.

"New Zealand police had requested confirmation whether the person who might be related to a crime case was in South Korea," the police officer said, adding that given her past address and age, she could be the mother of the kids.

The Safestore facility in Papatoetoe. Photo / NZ Herald

The Herald reported on Saturday that family members of the two dead children were believed to be in Korea.

Sources earlier confirmed to the Herald that family of the two young children are in Asia.

In a press conference last Thursday, Detective Inspector Tofilau Faamanuia confirmed NZ Police were also working with Interpol as part of the homicide investigation.

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

The remains were discovered on August 11 when people living at a Moncrieff Ave, Manurewa house brought "unowned property" to the address, which they had purchased during an auction from the storage facility.

They made the grim discovery as they opened the suitcases, sparking a homicide investigation.

Vaaelua also said the children were between five and 10 years old and had relatives living in New Zealand. It's thought their remains had been in storage for several years.

Police stressed that the family that found the bodies are not connected to the deaths.

Vaaelua said police were also making "very good progress with DNA inquiries".

He confirmed the bodies of the children had likely been stored in the Papatoetoe Safe Store storage facility for three to four years before being discovered.

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

The grisly discovery was made at a Moncrieff Ave property in Manurewa. Photo / Dean Purcell

He was, however, 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.

When asked if police knew the identity of the people who were renting the storage unit, Vaaelua said: "Yes, we are following positive lines of inquiry in regards to the storage unit with the assistance of the storage company."

Vaaelua said the family who found the bodies were "understandably distressed by the discovery, and they have asked for privacy".

"We are ensuring there is support in place for them."

A neighbour earlier told the Herald there was "kids stuff in the back of the trailer", which transported the suitcases, such as prams, toys and a walker.

"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," Vaaelua said.

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