A scientist helping to look after an orphaned orca believes his family will almost certainly return, it is just not known when.
Baby orca Toa has been cared for around the clock after becoming stranded at Plimmerton Beach on Sunday afternoon.
The Department of Conservation said yesterday the operation was at a "delicate stage" with "all options ... on the table" about what to do next.
Stormy weather meant Toa was transferred from a temporary pen by the shore to a portable pool.
And it halted air and sea searches for orca groups for a second day - with 4m swells expected this weekend.
If Toa's pod or another family of the animals can be found he may be able to be returned to the wild.
Orca Research Trust founder Dr Ingrid Visser said she had been keeping tabs on the baby orca's pod for the past 25 years.
"All orca are driven by the culture of their families, so they learn from their mums and their sisters and their aunties and everybody in their family.
"For some groups that culture might be that they would roam over big distances and they just turn up infrequently in some locations.
"And then for other groups they return to the same areas repeatedly."
The orca calf was shifted into a temporary holding pool on Thursday night. Photo: Department of Conservation
She said Toa was from a group that returned to the same places frequently, and the "chances are" they would return to the Plimmerton area.
"But the thing is we just don't know when.
"And so, to maximise the chances of getting him back to his family we are absolutely reliant on the public reporting any sightings of orca."
She said people should call 0800 DOC HOT if they saw any of the mammals anywhere nationwide.
There were no sightings of orca pods in the lower North Island yesterday and bad weather means there will likely be no air or sea searches this weekend.
Visser said Toa was in good condition - he was alert and had been playing with seawater as it was being pumped into the pool.
Rescuers care for the stranded baby orca at Plimmerton, Wellington. Photo: RNZ / Dom Thomas
Toa is a social creature and has a couple of volunteers with him in a pool 24/7 to keep him company.
But Visser said Toa's time with humans would not give him a scent that would make an orca pod reject him.
"Orca don't have a sense of smell, so we're not going to leave our scent on him."
DOC said there was no public access to the pool where Toa was being kept, and asked people to stay away.