A spate of bomb threats received over email in New Zealand workplaces is under investigation by police.
This morning Government cybersecurity agency CERT NZ confirmed it was aware of "a campaign of bomb threat blackmail email".
The emails are also being received internationally.
"The emails claim to have planted an explosive device in the user's office," CERT said in a statement.
"New Zealanders have reported receiving threatening emails that claim an explosive device is hidden in the recipient's office, and will be detonated unless an amount of ransom in bitcoin is paid.
"While this is likely to be an opportunistic scam, New Zealand Police are treating this as a real threat until confirmed otherwise.
"If you receive the email, we encourage you to contact New Zealand Police on 111."
Police confirmed they had received three reports of an email threat being received this morning.
"We are working to determine the validity of the threats," said a spokeswoman.
"At this stage the threats appear to be similar to hoax/scam threats received overseas."
CERT advised recipients not to respond or try to contact the sender.
"Do not pay the ransom or take any further action until you have spoken to New Zealand Police.
"Keep the email as evidence to pass to New Zealand Police."
One of the threats was received in Glenfield at a commercial premise.
Police said the building has been evacuated as a precaution.
Specialist search groups are currently clearing the building.
There is no further information available at this stage.