I posted this on Freedominion.ca. It should be a useful starting point: :)
We currently have 122 members in Parliament according to the election results last night. Labour is in the lead with 50 seats, National 49, United Future 3, ACT 2, Progressives 1, Greens 6, Maori 4, New Zealand First 6.
Labour, Greens, and the Progressives are obviously on the Left and they get 57 seats in Parliament. If they add Maori to the lot they are squarely at the half mark at 61. They can form a minority government but won't be able to pass legislations that really matter. National and ACT combined form the Right and they get 51 seats. United Future helped Labour last time but they will not support any government with the Green Party MPs as cabinet ministers. If they get together and have New Zealand First's support they also have 61 seats - able to form a minority government likewise.
New Zealand First's governance has a lot of Pat Buchanan paleoconservatism and populism in it. It may support Labour on a confidence and supply fashion but bear in mind it is poles apart from the Green Party so there will be some critical social and foreign affairs stance that Labour's Left go with Green support, but will be opposed by the New Zealand First. In other words even if Labour wins this time it will be a lame duck for this term - the Left can't pass anything important without centrists and even paleoconservatives' support.
To complicate matters we still have 193,000 special votes to be counted. Labour only leads National by 20,000 overall. And according to the current electoral laws the Green Party had not won any electoral seats so to represent in Parliament they have to pass off the 5% threshold which they have done barely, at 5.1%. If these special votes show a dismal performance by the Green Party, the overall share of Green Party votes could go down to 4.9% and Labour's chance of governance would be toast because the Greens are gone. And National and ACT could receive a lot of votes and tilt the balance towards the Right.
A blog has good information on the results:
Election postmortem