A 29-year-old man has been charged with murder after the body of a Whangarei woman was found in a stream early this morning.

Police are not looking for anyone else in relation to the 21-year-old woman's death, detective senior sergeant Dene Begbie said.

The man and woman were known to each other.

Police launched a homicide inquiry after they were called to the discovery of a woman's body in the Waiarohia Stream, Whangarei, about 4.20 this morning.

They believe they know who the woman is, but won't be able to formally identify her until they have the results from an autopsy, which was conducted in Auckland this afternoon.

Police wanted to talk to anyone who was in the Tawera Road area overnight and up until about 4am.

"Someone may have seen something unusual that has caught their eye or noticed suspicious activity around Tawera Road and Porowini Avenue," Begbie said.

"Any information could help us establish what may have happened before the woman was found in the stream."

About 30 police, including investigative, road policing and frontline staff, have been involved in the inquiry today and Police still have a large number of people to talk to and a number of scenes to examine.

Cordons were placed around the area but police have now allowed access to the Tarewa Shopping Centre from the Walton Street end of Tarewa Road.

The site is just down the road from the Northland Club, where Prime Minister John Key spoke last night.

It was understood that there was a protest outside the club last night, but police do not believe the woman took part, Begbie said.

Twenty police were working on the inquiry and the identity of the victim was yet to be confirmed.

Police are asking anyone that was in the central city in the early hours of this morning, in particular the Tarewa Road area, to contact the Whangarei police on 09 430 4500.

- © Fairfax NZ News