The Rotorua Lakes Council customer centre will reopen at 9am tomorrow after a white powder incident today.
An envelope addressed to Mayor Steve Chadwick containing a large amount of white powder was opened by council staff.
The plain envelope was opened by staff at 8am, the council's chief executive Geoff Williams said.
He said the council was treating the incident seriously, but staff were likely to have already presented symptoms if the powder was a hazardous material.
"We are obviously very concerned and are treating this seriously, but having said that at the moment the fire service are suggesting its unlikely to be a hazardous material and if it was it is likely to have affected people immediately, so we are not overly concerned but are still treating it very seriously.
"Our call centre staff are fine but it was obviously a traumatic event for them and we'll be providing them with any support they may need. We've sent them home for the day but will follow up with them."
Mrs Chadwick had no suspicions as to who sent the envelope and said it was "out of the blue."
"This is out of the blue to me personally, this is the first incident of this heightened concern."
"My family have been notified...This is sometime that goes with leadership and it's very sad really that there are people out there that feel so strongly, there are other ways to express themselves, but we will see what it is about as the forensic evidence unfolds."
Mrs Chadwick said she experienced a similar incident while she was still in Parliament, during the time she was progressing New Zealand's smokefree legislation and when she also received death threats.
"I feel very reassured by the immediate response taken by council staff, police and the Fire Service and very comfortable that all the right things are being done," she said.
Rotorua police area commander Inspector Bruce Horne said the police had begun an investigation, and would know within 24 hours if the substance was hazardous.
"It's a really early stage for our investigation. We have uplifted all relevant items of interest from the Fire Service.
"Our CIB is investigating. Our first step in that process will be to have the items forensically examined and the priority here is to give some peace of mind to people who have been exposed to this powder, to see if it was something untoward or not.
"We will know within 24 hours if it's anything to be concerned about determining exact substance might take longer."
Image 1 of 8: Fire crew get decontaminated outside the council building this morning PHOTO/BEN FRASER
Mr Williams said council staff had acted appropriately.
"On opening it they were very concerned and immediately contained it in a box, notified the police and also the fire service.
"Both responded very quickly, we contained and in fact evacuated most of our building, shut down the air ventilation systems and so on, so there was no concern of spread to the staff.
Police and fire service staff have been called to Rotorua Lakes Council Civic Centre after white powder was found in a letter opened by a staff member.
The doors to the council building had been locked and sections of the building had been quarantined, a council spokeswoman said.
The building has not been evacuated at this stage.
A reporter at the scene said two fire engines and the hazardous materials unit were outside the front entrance of the Civic Centre. Police are also at the scene.