Senior Sergeant Phil Le Comte, of Mid North police, said the flier was being examined by the Police Documentation Examination Team in Wellington and the Fingerprint Section in Auckland, as per standard protocols.
Once those inquiries were complete police would reassess what further inquiries were possible in Kerikeri.
The investigation was continuing, Le Comte said.
The Prime Minister's office did not wish to comment on the threat, saying it was an operational matter for the police.
It's not the first time the Prime Minister has been threatened.
In 2020 Auckland man Michael Cruickshank was charged in relation to two emails sent to Ardern and then Justice Minister Andrew Little in which he wrote ''I will personally wipe you off this planet'' and ''I will blow your head off''.
The messages were part of a barrage of 88 lengthy emails sent over a four-month period.
A 30-year-old Auckland man was charged with threatening to kill the Prime Minister in 2021, and in 2019 a man in Northern Ireland was sentenced to community service for threatening Ardern via Twitter after the Christchurch mosque attacks.
• Anyone with information about the Kerikeri threats should call police on 105 quoting file number 211202/0952.
