Northland's new MP Winston Peters has confirmed he will resign from the list - making it harder for the Government to govern.
Government loses its majority on planned environmental law changes and has to start again.
OPINION: The post-mortems in National over its crushing defeat in Northland are already under way.
John Key says the Black Caps should be immensely proud despite their loss in Sunday's Cricket World Cup final.
Prime Minister John Key admits National has been delivered a message by Northland.
OPINION: The post-mortems in National over its crushing defeat in Northland will be long and hard and are already under way.
OPINION: Shockwave. That is what will be going through National after the Northland rout.
Live results of the by-election: The votes are in and it's a Winston Peters white-wash.
It's going to be tough to match the excitement of last night's Black Caps win today, given even the halls of Parliament will be dominated by chat of the historic victory.
From Japan to Northland, the PM is wasting no time in trying to gain the almost certain lead NZ First leader Winston Peters has in the race for the Northland seat.