How quickly are agencies required to respond to Official Information Act requests? The law is very clear: "as reasonably practicable". While there's a 20-day limit, this is a backstop. When they're actually meant to respond is "immediately".
So do agencies do this? Of course not. And thanks to a long series of requests filed using FYI, the public OIA request website, Mark Hanna has the statistics to prove it. Pretty much every agency investigated showed a huge spike in their responses at the 20-day limit, and usually responded on the day a request was due. In other words, they weren't responding as reasonably practicable as required by law, but instead treated the 20 day limit as a target.
Some of this is due to explicit game-playing to delay release, as admitted by John Key. Some of it can be explained by overworked public servants having to prioritise their workflows and so not dealing with requests until they have to. But either way, it is not acceptable. The law says that requests must be dealt with "as reasonably practicable". And clearly, that law is being ignored.
As for what to do about it, Hanna suggests better reporting on timeliness, so that agencies can be held to the "as reasonably practicable" standard. That's a good idea, since we can't manage what we don't measure. But I'd also add that we need a culture shift within the public service to make handling public requests for information a priority. That can only come from the top, from Chief Executives and Ministers, and it must be backed by funding, so that OIA staff have time to handle things quickly, rather than having to juggle requests and so process them in deadline order. Sadly, despite all its talk in opposition, and even appointing a "Minister for Open Government", Labour seems uninterested in displaying this sort of leadership on transparency issues.