Local Government Minister Nick Smith has referred an email from the chair of the Mangawhai Ratepayers lobby group to police.
Dr Smith said he interpreted the email from Bruce Rogan about rate setting in the Kaipara District as a threat against himself and his children.
Mr Rogan wrote to the minister appealing to him to intervene over the issue.
His email said: "It's time for some accountability...we detect the smell of burning flesh" and referred to Dr Smith's personal safety and the kidnapping of a precious child.
Mr Rogan has since apologised, saying his colourful language was misinterpreted, and he means no harm to the minister or his family.
A review carried out by a law firm has confirmed that the council failed to comply with the statutory requirement for setting the rate and last month the district's mayor apologised for the council's rating blunder.