The reason for the closure is an outage of a number of online systems operated by the New Zealand Ministry of Economic Development (MED) which occurred during preparation work on Saturday evening to upgrade the servers hosting these websites. The websites will be unavailable until at least midday on Wednesday 28 September (New Zealand time, of course).
Due to the decision to declare IPONZ closed, if a deadline for filing an application or document falls on Tuesday or Wednesday this week, then the application or document can be filed on the next day when the Patent Office is open (i.e. Thursday) and will be deemed to have been filed in time.
Due to the short notice, however, IPONZ is open today (26 September 2011), despite the unavailability of its online systems. Email communications remain available (to firstname.lastname@example.org). The MED notice indicates that requests for extensions of time to meet deadlines falling today are likely to be viewed favourably by IPONZ, so long as they meet the normal requirements, including the provision of a reasonable explanation as to why the deadline was missed.
Full details of the impact of the outage, and the implications of the IPONZ closure, are available in a notice on a (working) MED website.