Mr Brill said the phone call included threats of violence towards Work and Income staff.
"Given the circumstances at present, police have taken precautionary measures and have closed the office."
A Rotorua Daily Post reporter at the scene said there was sign on the door and the office doors were locked. There were no staff members inside and police couldn't be seen.
Canterbury Winz offices closed down following threat
Meanwhile, police investigating a threat that shut down all Work and Income offices in Canterbury this morning say they have spoken to the alleged suspect and concluded there is no threat to staff.
The Ministry of Social Development closed all Canterbury sites as a precautionary measure after being made aware of a verbal threat against Housing New Zealand staff in Christchurch.
Police said they received a complaint shortly after 9am of an alleged threat by phone to a Housing New Zealand office.
Officers had investigated and spoken at length to the complainant and the alleged suspect, a police statement said.
"As a result of investigations, police are confident that there is no threat to anyone in this particular case," it said.
"Police take all such threats seriously and our top priority will always be to ensure the safety of staff and the public and respond accordingly."
Extra security at Winz offices
Authorities have put in place 100 extra extra security staff at Work and Income offices around the country and beefed up a police presence in Christchurch since a spate of incidents following Monday's double homicide at Ashburton's Winz office.
Ministry of Social Development chief executive Brendan Boyle and Deputy Police Commissioner Viv Rickard held a press conference today about threats to Work and income sites over the past two days.
Read more:
• Clients often get angry, says ex-Winz worker
Since Monday there had been nine incidents at sites around the country, including phone threats and a smashed window.
"People cannot and should not be able to threaten people in their workplaces without consequences," Mr Boyle said.
The organisation was taking a "zero tolerance" approach to any threats, he said.
As well as 100 extra security staff at sites around the country, police were also based in or near all Christchurch Work and offices.
Incidents since Monday have included verbal threats against staff in Christchurch and a threatening call to staff in Blenheim.
Other offices had been targeted in places including New Plymouth, Hastings, Thames and Nelson.
The extra security measures would be in place until further notice, Mr Boyle said.
The security officers would not be armed but were there as a deterrent and to diffuse any tense situations, he said.
Staff countrywide were feeling "on edge".
"There's a tremendous amount of...nervousness," Mr Boyle said.
Mr Boyle said the department was already aware of clients who were disgruntled and already had a system in place to deal remotely with them.
Mr Rickard said the police response to any incident at a Winz building would be "swift and fair".
"Arrests would follow where there is evidence to do so."
Of the people involved in the nine incidents, the majority had had previous contact with Winz staff, Mr Rickard said.
Ashburton man Russell John Tully, 48, has been charged with two counts of murder and one of attempted murder over Monday's shooting.
Police said today they found the firearm they believed was used in Monday's double shooting.
Tributes flow for the Ashburton victims and survivor:
Peggy Noble
Leigh Cleveland
Lindy Curtis
- APNZ, Rotorua Daily Post