Tiritiri Matangi sits just off the end of the Whangaparaoa peninsula north east of Auckland city you can catch a ferry from either Gulf Harbour marina on the peninsula or from Auckland city wharf, the trip from Auckland city is around 75 minutes each way, while from Gulf Harbour around 20 minutes, or if you are lucky go by yacht which i did that was cool because i had never been on a large yacht before and got to steer as well, if you go by Auckland you get to see alot more on the way out there.
You will arrive at the Tiritiri wharf the best way to start is to walk up wharf road to the visitor center right at the top of the island which is not that far up the road at least here you can see all the information on the tracks. Now you need to head back down the wharf road untill you get to grahams road which runs into ridge road this is the back bone that all the other tracks run off, ridge road actually runs right out to the other end of the island.
The island is 220 hectares alot of the tracks through the bush are laid with wooden planks to protect the habitat there are some fairly steep climbs but all round an easy walk.
There is no camping on the island which is a bit sad as it is a awsome retreat from the city but being a wildlife reserve i guess that is due, there is also no fires no where on the island at all including smoking, the walk through the native bush sections are awsome as there are alot of rare birds on the island so bring along the camera.
There is a bunk house for over night stays but they need to be booked months in advance as there are very limited bunks available. you can bring your fishing rods as well and walk right out to the other end, there are some fantastic rock platforms there.