A full examination, which started early this morning, remains underway in a bush area on Scenic Drive, in Waitakere.
The last confirmed sighting of Ms Millane was at 9.41pm on December 1, the day before her birthday, at the Citylife Hotel in central Auckland, when she was seen with a "male companion".
Formal identification would take place Monday, but police were confident the search for Millane had come to an end.
Police have said the examination is a "methodical and slow process and is expected to take all day".
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He said the United States provided a "minuscule" $20bn (£15.6bn) in aid. "The last thing we want is to have chaos in Afghanistan". The Pakistani envoy said that it was evident that neither the Coalition nor the Taliban could impose its will on each other.
"I can now advise that a short time ago, we located a body which we believe to be Grace", he said.
She graduated from the University of Lincoln in September with a degree in advertising and marketing and had embarked on a year-long worldwide trip.
After arriving in New Zealand on Friday, David Millane spoke with media.
Anyone who saw a vehicle matching the description on December 3 between 6am and 9.30am in the west Auckland area has been advised to contact police on 0800 676 255.
Saturday, police said they believed Millane was dead and that a man seen with her in Auckland the night she disappeared will be charged in her death.
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Univision reported that the family is seeking asylum and hoped to join family in Columbus, Ohio, while their cases are pending. An AP video journalist also witnessed more than two dozen migrants scale a fence between Mexico and the US on Monday evening.
Investigators also forensically examined the hotel where she was last seen.
Grace's father David Millane described her as a "lovely, outgoing, fun-loving, family-orientated daughter".
On Saturday police released images of a pink watch and a necklace belonging to her and asked for the public's help in finding them.
Grace Millane, who was travelling the world after finishing university, went missing on December 1 in Auckland.
Beard said Millane had been out of contact with her parents for days and they were especially anxious that they could not reach her Sunday for her 22nd birthday.
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For the same reason, Australia's government blocked China's telecom giant Huawei from its 5G mobile network last summer. Concern now centres on the deployment of fifth-generation (5G) mobile networks, where Huawei is at the cutting edge.
Her family was surprised and anxious when she didn't contact them on her birthday or get in touch over on the days that followed.