Thanks Peter, i've already been to DOC and they sent me here. They did mention their Arbourist was away at the time and suggested this forum was the best place to ask.
Melody McLaughlin <mmclaughlin@doc.govt.nz> 19 Feb (7 days ago)
Hi Ben,
Thank you for checking in on the Kauri. Below is the contact address for MPI and I have cut and pasted a section from their website regarding Kauri dieback if this is a possibility. Extreme weather conditions may also be a factor/cause. If you send through the photos I can forward to the National Plant Conservation Network and ask them or you can go onto their website yourself and ask?
http://www.nzpcn.org.nz/ This has a bunch of experts behind the scene who can provide expert advice.
MPI Hotline below.
Pest-and-disease hotline - 0800 80 99 66
From the MPI website a description on kauri dieback is below.
"An infected kauri may have:
yellowing leaves
a thinning canopy (the leafy, top part of the tree)
dead branches
large lesi