Labour's quietly optimistic it can get the seat of Christchurch back in the red.

The supposedly safe Labour seat went blue in 2011 won by National's Nicky Wagner.

Labour candidate Tony Milne says last time round, the quake and population shifts were a factor in the loss.

"People give government a lot of leeway initially after a disaster but four years afterwards we have a major housing crisis in our city.

"We've still got around 25,000 people waiting for their EQC insurance issues to be resolved and the government is not showing leadership in any of those things."