The Ministry for the Environment has apologised for an email that revealed the private email addresses of more than 100 people.
It follows two recent privacy breaches by the Earthquake Commission.
A ministry spokesperson, Andrew Bristol, says a message was sent to 147 recipients on Thursday night, informing them that consultation on changes to the Resource Management Act was closing.
He says rather than their email addresses being blind carbon copied, they were carbon copied - or cc'd - meaning they could be viewed by everyone who received the email.
A second email was sent a short time later, asking people to delete the earlier message.
Mr Bristol says the ministry has apologised for the error and is reviewing the incident to see if changes need to be made.
He says no other private information was disclosed.
