I should have added that we have been to Rotarua and not looking to include in Auckland vicinity trip

Head North to Russell/Paihia/Bay of Islands. Check out the sights on the East Coast route (don't overlook the Hundertwasser Toilets) and stay in Paihia or thereabouts. Enjoy the Treaty Grounds and numerous other sights. Take an excursion to Cape Reinga/90 Mile Beach if you can (it's probably best to join a tour for that stretch: you'll see the corpses of cars that got stuck in the sand). Return to Auckland via the Kauri forest and museum on the West Coast. Or vice versa.

I second what someotherguy said, head north see Cape Reignga and the Kauri Forests.

Lots to see and do in Bay of Island. In addition to Russell (you catch the ferry to Russell from Opua) and Paihia, also have a look at Kerikeri.

Yes, Waipoua Forest (home to the giant kauri) is a must-see.

If you stay in Paihia or Kerikeri for a couple of days and have time, drive up to the seaside village of Mangonui for lunch.

Here are a few links:
http://www.russellnz.co.nz/
http://www.paihia.co.nz/
http://www.doc.govt.nz/parks-and-recreation/places-to-visit/northland/kauri-coast/waipoua-forest/
http://www.hokianga.co.nz/
http://www.northlandnz.com/about/features/northland_must_dos/west_coast/waipoua_forest/
http://www.fodors.com/community/australia-the-pacific/nz-bay-of-islands.cfm
http://www.waitangi.net.nz/

Thanks very much Diamantina - much appreciated

We just got back from a week on the North Island, and our favorite part was the Coromandel Peninsula. It was absolutely gorgeous, with a great drive up the west coast, lush green sheep covered fields on one side and the water on the other. We stayed at Simpson's Beach (on the East Coast, north of Whitianga, for three nights, and visited the Hot Water Beach and the Cathedral Cove. We also visited Paihia for two nights, and enjoyed it, but to us it didn't compare with the Coromandel Peninsula. Also, one morning while in Auckland, we visited Karikari Beach and Piha Beach, and they were stunningly gorgeous. I'm working on a trip report, but thought that I'd go ahead and put in my two cents worth!

Many thanks CindyW for some really useful info

Cheers

What cruise ship will you be on twinkle60, my daughter and son-in-law will be gigging on the Sea Princess doing that trip from early Dec to end of February.

We recently did a four day trip to the Bay of Islands, hired a car, and drove up the West Coast and came back the East Coast. Didn't get as far up as Cape Reinga though. We stayed in Pahia and had a great time seeing the sights.