Two children at the centre of a major police hunt may have been picked up and driven away in the dead of night from near their caregiver's home.
Police hold growing concerns for a brother and sister who disappeared from a rural South Auckland property on foot last night.
They have not been seen for more than 12 hours.
At a police conference police said they were still not sure why the siblings had fled the property.
"I am unsure why but it appears they have left on their own accord," said Inspector Lane.
The children had family contacts in the greater Auckland area and police believed this was where they were possibly headed.
A woman was seen leaving the property where the children were last seen in her own vehicle.
Police last night launched a major search and rescue operation on land and air as they look for 15-year-old Te Morehu McLean and his 7-year-old sister Anahera.
The young pair left their Potter Rd home in Tuakau around 10pm carrying a large suitcase, the little girl dressed in a bedtime onesie.
Now police are broadening the search area and even looking at the possibility the siblings were taken out of the area in a pre-arranged rendez-vous.
"While the pair left on foot we are looking into the possibility they may have been picked up in a vehicle by someone known to them," said Inspector Kay Lane.
"We believe they may be heading north towards Auckland where they have extended family and would like to hear from anyone who has information about their whereabouts that may help us find them."
Police were continuing to search the wider Tuakau area this morning and speaking with neighbouring property owners to check their sheds and outbuildings.
Police say they are concerned for the missing children's safety.
This morning Potter Rd resident Bert Schreurs told the Herald he heard a noise near his house between 10 and 11pm and got out of bed to investigate.
"I heard a door closing. I went outside and looked right around the house but there was nobody there."
Schreurs had also noticed fresh tyre marks on a gravel drive at his nearby unoccupied rental property.
He said the metal had been disturbed where a car appeared to have turned around.
However, he was not sure if it was from a search party or connected to the sibling's disappearance.
Nothing had been disturbed or taken from inside the house.
Schreurs said only a few houses were dotted along the dead-end rural road and it was generally very quiet.
Schreurs didn't know the children but would see children at the property during school holidays and weekends.
One of his neighbouring properties took in children during weekends and holidays.
The property is a small dwelling 40m from the road and fixed in a rural secluded setting, 5km from the main settlement in Tuakau.
The property can be seen from the road and is a dark brown.
It is not obvious children reside at the property.
A horse can be seen grazing in front of the property in a fenced off area.
Police have widened their search to the greater Tuakau area.
This morning police asked residents to look in buildings and sheds for the pair.
Anahera was last seen wearing a Frozen-type onesie. She is described as being average height and small build.
Te Morehu was last seen wearing Nike shoes, light-brown pants and a Kathmandu puffer jacket. He is 170cm, solidly built with short dark hair.
It's believed the pair are likely to be in the Auckland or Waikato areas.
Police want to hear from anyone who may have information on their whereabouts.
Anyone with information can contact Counties Manukau Police immediately on (09) 261 1300.