Local Government Online had a nifty portal last year for the local body elections. Well they have used that template to do the same for the general election – at vote.co.nz.
They list the candidates for every electorate, plus all the parties and their lists. Parties and candidates can upload material to it, and you can ask questions to the candidates.
I found their sister site for local body elections really useful, and this one should be a great resource also.