Police are carrying out a full scene examination in a bush area on Scenic Drive in Waitakere as part of their investigation into the death of Grace Millane.

The search would be "methodical and slow" and was expected to take all day, Detective Inspector Scott Beard said.

"We are not able to confirm whether Grace has been located at this site," he said.

Scenic Drive will be closed between the intersection of Mountain Road, Scenic Drive and the Waitakere Reservoir Carpark from 3pm until 7pm tonight.

Residents will be given access during this time.

Yesterday police announced that a 26-year-old man who had been speaking with police about the disappearance of Ms Millane will be charged with her murder.

He will remain in police custody until Monday morning, when he will appear in the Auckland District Court.

The 26-year-old is the same man who was questioned previously by police and was with Ms Millane at several places, including Sky City, before going to CityLife Hotel with her.

The Millane family has requested privacy and will not be making any further statements at this stage.

Mr Beard briefed media in Auckland earlier this afternoon and said they were treating her disappearance as a homicide.

"The evidence we have located so far, our scene examination, some of the CCTV footage we have, and our investigation has determined that Grace is no longer alive and this is a murder investigation," Mr Beard said.

"A 26-year-old man was located at a central Auckland address by police. He was brought back here to Auckland Central Police Station and is currently speaking to us in relation to the murder of Grace Millane.

"Grace's family have been advised of this development and they are devastated."