Detective Senior Sergeant Zane Smith said Rotorua CIB has executed a search warrant at a residential house this morning.
He said he could not comment any more as it was an ongoing investigation.
He would not say if anyone had been arrested or taken away by police at the property.
A police forensic team is at the scene of a property on Clayton Rd.
There are six police cars parked outside the house.
Two sheds at the house have been searched by police. A reporter at the scene said one of the sheds looks as if a door has been kicked down.
Nearby schools St Michael's Catholic School and Western Heights Primary School were both unaffected.
Western Heights Primary School principal Brent Griffin said they were aware of the police operation down the road but said they had been in discussions with the police and had been told there was no need to go into lock down.
St Michael's Catholic School did not know anything about the incident when phoned by the Rotorua Daily Post.
Armed police have now left the scene and the cordons have been removed.
Wonderworld Aquarium and Pet Centre owner Ardie Drummond said there were "cops everywhere".
He said he only became aware the road in front of his business was blocked off when his sister rang him.
"Looking at them they are driving past."
He said the road outside his business was closed but there were still people walking up the street.
"I didn't even know. I was thinking [business] it had been quiet."
"They [ the police] have got all their guns out."
An armed offenders squad operation is in place in the Western Heights area - with several roads closed.
Inspector Ed Van Den Broek from the Rotorua police said the armed offenders squad operation had been going on for "a couple of hours".
He said several roads were closed as a result.
Mr Van Den Broek said he could not provide more details but said there was nothing for residents to be worried about.
A reporter at the scene said cordons were up on Clayton Rd between Brookland Rd and Steeles Ln.
An armed police officer is at the cordon near Steeles Ln.
Detective Senior Sergeant Zane Smith, who is the officer in charge of the case, said more details would be released late morning.