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 said they 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.
In late November police searched hospitals and schools throughout the country after many received threatening emails.
Among them, Auckland's Saint Kentigern College was evacuated and Wellington Hospital, Bowen Hospital and Burwood Hospital were searched, and police sent to Dunedin's synagogue.
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.
"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."