The Official Information Act 1982 (OIA) allows anyone in New Zealand to request information from a large number of government agencies, and lays out responsibilities for how they must respond. This includes timeframes and reasons that will allow some information to be withheld.
The OIA is a great tool for anyone intent on holding the government to account. It is indispensable for many journalists and activists, and also useful to anyone who might just be curious about some piece of official information. I've written a guide to using the OIA, which you can find at oia.nz.
Section 15(1) of the OIA requires that decisions on what information should be released must be made on a request and communicated to the requester (including any information to be released) as soon as reasonably practicable, and in any case not later than 20 working days from the time the request was received. There is a clause that allows for extensions to be granted if necessary.
In an ideal world, this would be fine. However, in my experience it leads to the "20 working days" being used as a target, rather than a limit that must not be exceeded. In some cases, delaying requests as long as possible may even be used as a deliberate tactic by the government, against the spirit of the OIA.
FYI is a website that allows OIA requests to be made publicly, with the response also being made publicly available. I've made a number of requests for official information via this site, and collated some data from it on this page.
Specifically, I've gathered data on the number of working days remaining before the deadline (including extensions) when I've received decisions on my requests, and the time of day at which it was received.
As you can see in the graph, there is a huge spike in responses received on the final allowable day, and it is not uncommon for responses to be received late.
These numbers are just for requests that I have made via FYI, and are unlikely to be representative of all OIA requests. If you are interested in seeing more comprehensive data, the Ombudsman and the State Services Commission have published some: First release of OIA statistics
I have also examined data released under the OIA regarding how long various government agencies take to respond to OIA requests. You can find links to the data and read my analysis here: Official information kept secret too long