WELLINGTON/SYDNEY (Reuters) - Law enforcement agencies in Australia and New Zealand are investigating bomb threat emails received by some residents, cyber security officials said on Friday, after similar threats were made in the United States and Canada.

“Given the widespread nature of these malicious emails, we have reason to believe this to be a scam,” the Australian Cyber Security Centre said in an email to Reuters.

“As a precaution, state policing agencies are treating these emails as a legitimate threat until confirmed otherwise,” it said, without giving details about the contents of the emails.

New Zealand’s CERT NZ said earlier police were working to confirm the validity of the threats, although they were likely to be an “opportunistic scam”.

The emails claimed a bomb would be detonated unless an amount of ransom was paid in bitcoin, it said.

A rash of bomb threats were emailed to hundreds of businesses, public offices and schools across the United States and Canada demanding payment in cryptocurrency but none of the threats appeared credible.