Situated at the tip of the Awhitu Peninsular is the Manukau lighthouse - info their web site - Manukauheadslighthouse.co.nz
An easy and very picturesque 100km drive from downtown Auckland - take some sandwiches and a drink as there is really nothing along the way. There are picnic tables, hand washing facilitates and toilets below the lighthouse.
A view from the lighthouse of the entrance to the Manukau Harbour and surf on the notorious bar (Wikipedia) and site of many shipwrecks in the distance.
View from the lighthouse looking back towards Auckland City.