- Labour Party - votes 40.60%, electorate MPs 31
- National Party - votes 39.76%, electorate MPs 31
- New Zealand First Party - 5.86%, electorate MPs 0
- Green Party - votes 5.09%, electorate MPs 0
- Mâori Party - 1.95%, electorate MPs 4
- United Future New Zealand - 2.74%, electorate MPs 1
- ACT New Zealand - 1.52% electorate MPs 1
- Jim Anderton's Progressive - 1.21%, electorate MPs 1
You'd have a parliament of 69, neither major party would have a majority, and they'd be negotiating a coalition.
Martin Stabe has done the same calculation for Germany.
Germany: don't blame proportional representation
Only half of the Bundestag owes its seats to state party lists and proportional representation. The other half of the chamber are actually British-style constituency MPs. A quick glance at the official results released by the Federal Returning Officer shows that an entirely first-past-the-post election would have led to more or less the same outcome.
If we simply ignore the half of the Bundestag that is elected by PR, and concentrate on the 299 MdBs elected by direktmandat (ie, the first-past-the-post constituency MPs), the composition of the new Bundestag would look like this:
SPD: 145 seats
CDU: 105 seats
CSU: 44 seats
Greens: 1 seat
Left: 3 seats
FDP: 0 seats
I guess you could argue that the fact of PR makes people vote differently, but that argument actually gives the game away. Since people are obviously freer to decide their vote under PR, it follows that more decisive systems are actually not decisive at all. Blair got 35.3% of the popular vote and 55.2% of seats. Clark got 40.6% of the popular vote and a 40.9% of the seats.
There's a whole separate argument about the political effects of SMD, suggesting that it encourages winner-take-all no-compromise results, but I'll go there another time. Our hairy-chested media analysts tend to confirm the theory when they insst that PR parliaments are weak-kneed and lily-livered on economic reform.