Bomb threats were made to more schools today.
A further 27 "concerning" calls were made to a number of schools around the county, Superintendent Chris Scahill said.
Police attended each school and worked with the schools management team to decide on the appropriate response. Police were investigating the origin of the calls.
"We should make it clear that while such calls may display a New Zealand number, they can still be originating from overseas," Mr Scahill said.
"Until police can rule out any actual threat, we must take all these calls seriously and respond accordingly."
Mr Scahill said the safety of students, teachers and schools was a priority.
"We understand the fear and concern that this will cause, however we reiterate that so far we have not established any actual threat to any school."
Police would not name each school to try and prevent further calls being made.
Kerikeri High School and Kaitaia Intermediate School in Northland, and Glendowie School in Auckland were three of the latest schools to have received threats.
The schools called police who checked the grounds and gave the all three the all clear just after 1pm.
"These calls were of a robot-like automated nature," Mr Scahill said.
Police believe today's calls may be linked to the events of Wednesday afternoon, where calls were made to six schools around the country including Napier's Tamatea High School.
Logan Park High School in Dunedin, Wellington High School in Wellington, Burnside High School in Christchurch, Central Normal School in Palmerston North, and Brookfield School in Tauranga also received threats about 12.30pm on Wednesday.
Tamatea High School principal Robin Fabish said it was back to business as usual today.
Mr Fabish held a brief assembly to thank the 305 students for their cooperation and his staff for their response.
"I reminded them that though the drills may be frustrating it was important that student safety was treated seriously."
"You just never know and we can't take those sort of risks."
He was still at a loss to explain why his school was targeted.
"It's very weird, we're an awesome little school of rockstars with no rivalries.
I just think it was totally random."
Mr Fabish said no students required any counselling as a result of yesterday's threat.