27% of my NZ net income, not including rates (around 29% including rates). But only around 18% of my total disposable income, including returns from my uk property and an occupational pension. I live in the Wellington wop wops, on the edge of Pauatahanui/Judgeford which gets you a lot more for your money. It doesn't surprise me A C Slater, that yours is higher. I've got a sense of that from a few of your previous posts about your budget. You are sticking pretty close to Wellington, so prices will be higher.
For $400 a week to represent 50% of your net income your gross income must be around $53k, which is not a lot for a sole earner family in Wellington. Survivable, but not a lot of wriggle room. That assumes you pay 3% kiwi saver, but don't get any work and family benefits.