Hospitals, religious institutions and other organisations throughout the country have received another barrage of "unsettling" and "concerning emails", after threats were made by email last month.
Police were working with those who received the messages, and each organisation would need to respond differently depending on what had been sent to them, and their individual circumstances.
Those earlier emails were bomb threats, acting assistant commissioner Naila Hassan said at the time, and police believed they were sent from overseas.
Among them, Auckland's Saint Kentigern College was evacuated as some students were sitting NCEA exams, Wellington Hospital, Bowen Hospital and Burwood Hospital were searched, and police were sent to Auckland City Hospital.
"This isn't targeted at any particular community or group, it is quite widespread" and police were working with overseas agencies to try to learn more, Hassan had said.
The latest round of emails were "similar to those received by a number of organisations on 23 and 24 November" and were "unsettling for all those concerned", police said in a statement on Sunday.
"We are working to establish the origin of the emails.
"Any threat received will be treated with the appropriate caution, however, police have not established any actual threat at this time.
"We ask that organisations who receive the emails continue to report them to police, to assist in our ongoing enquiries to identify the origin of the emails."