KEY POINTS:
Labour MPs frequently make snide digs at John Key's Parnell house and its location outside his Helensville electorate.
Last week, they used it in Parliament as part of an all-out attack on the National leader.
But Mr Key is by no means alone in living outside the boundaries of the constituency he represents. Of the 62 electorate MPs in Parliament, 12 are registered to vote in other electorates.
For some, representing an area away from home was a deliberate choice, others have moved away from the electorate for family reasons and, occasionally, it is the electorate that moves.
Labour's Waitakere MP, Lynne Pillay, bought a house in her electorate when she stood for the seat.
But then the boundary was moved a few doors up the road and her home become part of the neighbouring electorate.
Nothing - other than possible voter resentment at an "outsider" coming into their patch - prevents someone standing as a candidate in an electorate in which they are not enrolled to vote.
Mr Key said that when he first stood for Helensville, the fact that he lived elsewhere had been front-page news, so his constituents knew about it before they voted for him.
He has subsequently sold a house he owned in Waimauku, and also publicised that fact.
"The way the voters will judge you is on how effective you are at representing them and doing your job, not where you sleep at night," he said.
"These days I probably sleep more in Wellington than anywhere else."
Although his life has become much busier since he became National leader, Mr Key tries to set aside Mondays to work in his electorate.
"Sometimes it's not possible because of leader's commitments, but by and large I try and get there every week if I can."
Labour New Lynn MP and Cabinet Minister David Cunliffe moved to Herne Bay for family reasons, but the home he owned in Glen Eden is no longer in the electorate because of boundary changes.
He lives 10 to 15 minutes by car from his electorate, depending on traffic.
"I have made no secret of it," Mr Cunliffe said.
"I think my constituents have every right to expect that I am present and working hard and visible, and I do everything I can to make that the fact and the perception."
Labour Cabinet Minister Phil Goff moved out of his Mount Roskill electorate after losing his seat in the 1990 election, something a rival candidate made much of during Mr Goff's bid to win back the seat three years later.
"Gilbert Myles ran a major campaign on it in 1993 with billboards all over my electorate saying that I lived outside the electorate. It made not a jot of difference to my result in 1993, when I won the seat back off him.
"I don't think people want want control over all the aspects of my private life. What they want is accessibility and the knowledge that I'm doing the job conscientiously, and if they want help they will get it from my electorate office."
Mr Goff moved to a rural property in Ardmore for lifestyle and privacy reasons. But he says his electorate sees as much of him as ever, as he has frequent street meetings or and goes knocking on doors.
"I think I'm probably rare among MPs that I go through the whole of my electorate at least once a year, every year."
National Northland MP John Carter, whose electorate is one of the largest outside the Maori seats, made what he calls a pragmatic decision to live in fellow National MP Phil Heatley's Whangarei electorate.
After flying home from Wellington on Thursday nights, Mr Carter travels the next three days to hold clinics in the far-flung regions of his constituency.
"I don't think it's where you live, it's how effectively you represent the electorate," Mr Carter said.
Among MPs who have been cut off from their electorates by boundary changes, Invercargill's National MP Eric Roy is a veteran.
He has lived in four electorates without leaving his farm, and draft boundary changes for next year's election put him back in the Invercargill electorate.
"I'm virtually across the road [from the boundary] and 20 minutes' drive from the centre of Invercargill," he says.
Moving boundaries have also put fellow National MP Tony Ryall out of his Bay of Plenty electorate.
"I live about three minutes outside the electorate, in Tauranga," he said.
"Two-thirds of my electorate is Tauranga city, and I live out of Tauranga city but in the Tauranga electorate."