There is an excellent camping site at Sandspit that you can either use your tent or rent a cabin. I is only 1hr's drive from Auckland. The area is great and you will be right on the water and be able to watch the boats coming and going. You are 5 mins by car from 2-3 other beaches that have great areas to sit and watch everybody enjoying themselves – Omaha, Snells, Parkiri, Martins Bay. Plus only 10minutes from Matakana that has country markets, pottery, art galleries etc. Heaps to do and 2-3 lovely vineyards and restaurants if wanted.
If you are interested I would suggest you ring immediately as it is not a big camp and could get full for Easter.
References :
Sandspit Motor Camp – ph: 09 425 8610.
I live around this area and love the diversity of things to do all the time. Never get sick of waking up to a view of the water everyday.

I loved the Waipu Cove area. It is only about 2 hours north of Auckland and is a beautiful little area. I lived there for 3 months a while back and even around Easter time the water is warm enough (just) to have a bit of a splash around. The town of Waipu 10 minutes down the road is very quaint too.

Otherwise I love Paihi up in the Bay of Islands and you will always find HEAPS to do in Rotorua.

Have a great Easter break.
References :