Grace Millane was last seen going into the CityLife Hotel with a man on Saturday night, police say.
Detective Inspector Scott Beard this afternoon told media police hold "grave concerns for her safety".
Grace Millane was last seen at 9.41pm on Saturday, December 1 at the central Auckland hotel and police have spoken to the man she was with.
An apartment in the CityLife Hotel on Queen Street is a place of interest and police are now carrying out a scene examination.
"We still have no evidence of foul play, Grace is still missing," says Detective Inspector Scott Beard.
He says he was unable to discuss what man Grace Millane was last seen with.
Scott says the man is not in police custody, but is a person of interest.
And police have reviewed hours and hours of CCTV footage.
A missing person report was received on Wednesday for the 22-year-old after her family had not heard from her for several days.
Grace's father has arrived in Auckland today to help police in the search operation.
David Millane was met by police at the airport and is being supported by them today.
David struggled to hold in his emotions as he told media of his worry for his daughter.
"As a family we've been extremely concerned for her welfare.
"Grace is a lovely, outgoing, fun loving, family orientated daughter. She's usually in daily contact with family on social media," he says.
"Grace has never been out of contact for this amount of time and is usually in daily contact with either her mother, myself or her two brothers."
"Grace is on a year-long worldwide overseas experience. Grace started this travel journey in Peru in South America and was really looking forward to the second leg in New Zealand.
"She arrived here on the 20th of November and has bombarded us with numerous photographs and messages of her adventures.
"Finally, I would just like to take this opportunity to appeal to anybody who has seen, spoken to, or come into contact with Grace over the last few days, to come forward with any detail, no matter how small, and contact the investigation team."