Russell Brown and Media3 have discussed the lack of political TV satire in NZ. Being someone who has written and hosted political TV satire with the War on News, I'd like to throw my 5cents in.
I think good satire should be offensive to authority. At it's sharpest, news satire reveals uncomfortable truths to power in the manner of a shakespearean jester crossed with Max Headroom. That is a difficult line to walk in a country that takes 'Maaaaaaaori get too much' as it's median line in the debate on race relations.
7 Days is extremely funny, but it is more dick jokes than political satire. I think the last genuinely funny NZ satire was The Unauthorized History of NZ, but that may have gone over the heads of some.
Good satire is political and partisan and challenges the legitimacy of authority which is well outside the comfort zone of most broadcasters.
The advent of The Daily Show and Colbert Report has pushed news satire to a new level, the actual voice of the social critic. The critical analysis each of these shows has managed to bring to political and media issues makes them more credible than the news organizations they are reporting on.
Michael Moore started his TV career with 'TV Nation' and noted that while networks hated the challenge to authority his show generated, they loved the ratings it provided.
Sharp political satire that goes that extra mile can rate but few NZ broadcasters have the courage to produce it and the furore NZ on Air received over a child poverty documentary means they are highly unlikely to risk more political pressure by funding something that openly mocks the Government.
It'll happen, but it will require a broadcaster with some vision.