The three-year political career of National Northland MP Mike Sabin is in the balance after a report that he is under investigation by police over an assault complaint.

Prime Minister John Key yesterday refused to comment, instead directing media queries to police. However, police also refused to confirm either receiving a complaint or any investigation into allegations against the former detective and anti-methamphetamine campaigner.

Nevertheless, the Herald understands senior Northland National Party figures have already been discussing potential candidates to replace him in the event of a byelection.

Party president Peter Goodfellow told the Herald National's hierarchy was unaware of any allegations, historical or recent, against Mr Sabin before this year's general election. He refused to comment further.


Mr Sabin, 46, is understood to be receiving support from a caucus colleague.

The investigation into the assault complaint against Mr Sabin is being handled by police in Auckland's Waitemata district rather than in Northland, where he served as a detective and where it was claimed the events took place, it was reported yesterday.

Mr Sabin, who lives at Coopers Beach with his partner and is chairman of Parliament's law and order committee, did not respond to the Herald's requests for comment.

Mike Sabin, 46

*Former drugs detective.
*Entered Parliament in 2011 on the back of career combating methamphetamine.
*Joined the police in the mid-1990s after stints in the navy and dairy industry.
*Posted by police to Auckland, but soon moved back to Northland where as a detective he focused on drug enforcement.
*Left the police in 2006 and founded consultancy MethCon in response to P problem.
*Joined the National Party about this time.
*Stood for National in Northland five years later and retained the seat with a majority of 10,655.
*Held the seat at this year's election with a slightly reduced majority.