Tired and distracted Cantabrians still living in uncertain times might stay away from the polls in droves, election experts fear.
The greater Christchurch electorates are seen as key to winning on the national front.
And perceptions on the Government's handling of the earthquakes and Christchurch's $40 billion rebuild - and Labour's alternative plans -- could swing voters either way.
National won the 2011 general election party vote in Christchurch, and proved critical in securing the outright result.
But a lot has changed in the last three years. The landscape has shifted - literally, and metaphorically.
The rebuild of the flattened CBD is progressing at a frustratingly slow rate. Debates rage over whether the city needs a new convention centre or covered sports stadium.
Traffic snarls to a halt, a new street appears blocked off every day with the the orange road cones that have come to define the post-quake cityscape.
Red-zoned eastern suburbs continue to be bulldozed. Schools are being closed, moved, merged.
Many Cantabrians are still living in broken homes, battling EQC and insurance companies, dodging pot-holes, and worried about their jobs.
It all could lead to a low turnout at the polls.
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The 2011 election had a national voter turnout of 74.21 per cent - the lowest since 1887.
In last year's Christchurch East by-election, just 41.5 per cent cast votes.
Election experts warn it might be similarly low on September 20. Just don't confuse a potentially low turnout in the shattered city with apathy, Canterbury University political science lecturer Dr Bronwyn Hayward says.
"People are very tired, and very distracted with really basic administration," she said.
"I even forgot to vote in our local community board by-election last week, and I'm a political scientist...
"But like everybody else, we've moved our house, moved our parents, both our neighbours [houses] have been pulled down, just loads and loads of logistics going on."
Latest figures show that out of 168,996 properties with a building claim lodged with EQC, a total of 23,659 (14 per cent) have not yet been resolved. A third of 146,000 land claims have not yet been settled.
Earlier this month, the Insurance Council of New Zealand Insurance said payouts for Canterbury earthquake claims have topped $12 billion - with 80 per cent of commercial and 66 per cent of all residential claims having been fully settled.
Former long-serving, left-leaning Christchurch MP Jim Anderton, who retired from Parliament at the 2011 election, says the red-tape and bureaucratic wrangling has worn people down.
"There is a weariness here. Some people have lived in utter hell, and still are, and have put up with a huge amount of disruption, stress and strain. Even though elections are important, of course, it would hardly be surprising if their minds weren't completely switched on to elections of any kind, when they've got housing, insurance, work, and God knows what."
Mr Anderton is watching the election "with interest", but from a distance this year.
While he doesn't see any dramatic changes happening, he thinks the city's overall party vote will be crucial to the bigger picture.
"The party vote swung to the National Party last time and it helped them a lot. So if Labour could regain that - and I'm not close enough to it to know - that would be the biggest potential to create change."
Earthquake Recovery Minister Gerry Brownlee is odds-on favourite to retain his Ilam seat, most predictors say.
Mr Anderton thinks Labour's Megan Woods is a "certainty" to retain her Wigram seat, while party colleague Ruth Dyson is "quite a popular MP" in the Port Hills electorate.
National MP Amy Adams looks a solid bet in Selwyn to the south, Mr Anderton thinks, but the real contests will be in the Waimakariri, Christchurch East and Christchurch Central electorates.
"The Waimakariri seat of [Labour's] Clayton Cosgrove is a genuine marginal," he said.
Electorate boundary changes to Christchurch Central could unseat National's incumbent Nicky Wagner, local experts believe, while Christchurch East has long been viewed as a Labour stronghold.
Thousands have left those areas badly hit by the earthquakes in the three years, however.
How much will that displacement affect the polls?
"Who knows. They haven't just gone to one place - they've gone to Kaiapoi, Rolleston, Halswell...," Mr Anderton said.
The real issue will be just how much the Government has done to win hearts and minds in the region - and how well the Labour Party has presented an alternative.
"The jury is out on that," Mr Anderton said.
There are recurring themes in Christchurch - distraction, weariness, uncertainty.
Massive earthquakes and thousands of aftershocks mean that Christchurch will never be the same again.
Just what that means for the political landscape, only time will tell.
"This year is just too soon. I think it will be two to three election cycles before we know," Dr Hayward said.
• Christchurch Central - National, Nicky Wagner, incumbent since 2011.
• Christchurch East - Labour, Poto Williams, incumbent since 2013 by-election.
• Ilam - National, Gerry Brownlee, incumbent since 1996.
• Port Hills - Labour, Ruth Dyson, incumbent 1993-96, and 1999-present.
• Selwyn - National, Amy Adams, incumbent since 2008.
• Waimakariri - Labour, Clayton Cosgrove, List MP since 2011. National's Kate Wilkinson, MP since 2005, not standing.
• Wigram - Labour, Megan Woods, incumbent since 2011.