Acting Detective Inspector Tim Williams, Waitematā CIB, said a post-mortem examination has been completed.
“At this stage, we have not been able to confirm the identity of the victim, but we can say they are a female of Asian descent, possibly Chinese, and small in stature.
“Police are asking anyone who may have information on a woman matching the description who they have concerns for to please get in touch.
“Our priority will be to then identify and notify the victim’s next of kin.”
Williams said police were still unsure of the circumstances surrounding her death and would not speculate.
Anyone who was near the water in the last few days or in the Gulf Harbour area who saw anything suspicious is being urged to come forward with information.
”No piece of information is insignificant as we work to determine exactly what has occurred,” Williams said.
“We would like to thank those who have already come forward and given us information.
“Police appreciate this is very unsettling for both the Gulf Harbour and wider community and we reiterate we do not believe there is a wider risk to the public in relation to this death.”
Middleton was in the Whangaparāoa area to do some fishing, trying to catch some decent-sized kahawai or snapper.
He had gone to Army Bay in the morning but had not found many fish so went to try around the ferry terminal.
“I [cast] my lure out ... and nothing much was happening, but there was a bag out there,” he told Radio New Zealand on Tuesday.
He said that at the time he did not know it was a bag and thought it was a log or a dead animal. Boats had been passing through the area, near the entrance to the marina, he said.
“Anyway, the wind changed and brought it in to the coast. Anything floating in the water brings fish around, so I was targeting it. I got that perfect shot, like millimetres to the side of it.”
He hooked it and pulled it in to the shore - it was heavy but easy to move - and managed to pull it up the rocks a little.
“I took the hook out and thought, ‘Right, let’s see if it’s a bag of rubbish and I need to dump it in a rubbish bin or something’.”
He struggled through “layer and layer” of plastic to open the bag.
There was “a bit of clothing ... and then there was this hand sticking out”.
It was at that point that he called police.
“Two cops turned up and they thought I’d actually said there’s just a hand in a bag and then they went down there and went, ‘Oh no we’ve got a body’,” Middleton said.
Middleton had been fishing from rocks on the coast. He then dragged the object up on to the rocks, but not further out of the water because it was too heavy, the tourists said.
Once Middleton unwrapped the plastic around it and found a human hand, he returned to his nearby camper and phoned police.
Police have urged anyone with information to contact police on 105 or go online using the ‘update my report’ function and use reference file number 240312/9837. Alternatively, information can be provided anonymously via Crime Stoppers on 0800 555 111.