Actually, EU Member States Romania, Bulgaria and Cyprus are also not currently member states of the Schengen area along with the UK and Ireland.
From a brief reading of various sources, I think it may be possible to request a further extension to a Schengen entry permit once you are within in the area.
It certainly is a fact that for the purposes of a 90 day Schengen tourist visa, the Schengen member states are considered to be one sovereign area. This means you cannot spend say 90 days in Portugal and then nip over to Spain for another 90 days. It is 90 days total in all the member states of the area.
I would suggest that you should identify your first proposed entry point in the Schengen area and then contact that country's consulate in Auckland for further clarification on extensions..
A list of all diplomatic and consular missions accredited to New Zealand published by the New Zealand Ministry of Foreign Affairs can be found here.
…govt.nz/includes/pdf/PDF-Foreign-Representa…
Ah! I see the confusion. What I quoted was from an article on the main EU Schengen Authority website in Brussels.
This makes no mention of the continued validity and application of pre-Schengen bilateral agreements between NZ and individual Schengen states, as stated in thehttp://eeas.europa.eu/delegations/aus-nz/ website which you quote and which is the site for the individual EU Delegations in Canberra and Wellington.
I have some experience in this topsy-turvy world of diplomatic gobbledegook but I am not an specialist in International Law.
From what the latter site says, and it appears to be the case I agree, is that that you should be able to stay for individual stays of up to 90 days in different countries in the Schengen area with which NZ has such bilateral arrangements.
However, to put you mind at rest why not email or call the NZ Ministry of Foreign Affairs in Wellington to get a confirmed legal understanding of this matter from the NZ Govt. side.
Contact / Email query form here: