We are taking a cruise departing from Sydney & Melbourne, Australia which stops at Fjordland National Park, Dunedin, Christ Church, Tauranga and ends in Auckland. From Auckland we have a rented car for an additional 10 days and wonder if we should stay on the North Island or have enough time to fly to or take the ferry across and go on to the South Island also. Basically we want an opinion on how to best use our time for sightseeing and advice on whether to fly or take the ferry across between the islands. We've heard the ferry ride can be rough.

Normally I'd say 10 days isn't sufficient time to see both islands, but because you'll already have visited a few areas on both, it could work.

The ferry leaves from Wellington on the NI and arrives in Picton on the SI - it takes about three hours. I've heard it can be rough too, but I've never taken it. If you're interested in visiting Wellington and the top of the SI, I'd say take the ferry; whereas if you're most interested in the West Coast or say, the Queenstown area, I'd suggest you fly.

Keep in mind you can fly to several points on the SI, including Christchurch, Nelson, Queenstown and Dunedin, and a few others.

There's a recent trip report here written by indiancouple that you might want to take a look at. They covered a lot of ground in a sort time, covering both islands.

Thanks for your response. We did read the indian couples travel report and it sounded great! Hope we have their weather too.

We did a driving trip in New Zealand this pass Jan...about 11 days. We our flight was SFO to Auckland to Wellington for two nights then took the ferry to Picton. That was a beautiful trip and was not rough, well woth it. We then drove a loop down to the West Coast and on to Queenstown then on around to CC. The West Coast and Queenstown areas are worth seeing.

Look at our Blog for a day by day trip report with pictures. It might help you with your plans.

www.aroundtheworldin132days.blogstop.com

Thanks for the info. I would like to look at your blog but I can't get to it.

Sorry rodgerdvp, I left off the "/'".

Try this, I copied it from another of my Fodors reports that does link to the trip report.

www.aroundtheworldin132days.blogspot.com/

Don't know if the timing is right for you, Rogerdvp, but this group has a great deal on rental car or campervan, including free ferry for driver & vehicle, extra days at $50/$75 day

They often have specials, so it may be worthwhile to register for their email newsletters. www.standbyrelocs.com

Coming from a Kiwi, 10 days isn't enough to both islands and enjoy it. I'd focus on only the north island and possibly the top of the south. The ferry ride can be rough at times, but not often. I've been on the ferry 5 or 6 times and only ever had 1 rough journey.
Things to see in the north island that are worth doing:
Wellington
Forgotten world highway
Taupo
Rotorua
Hastings and Napier
Warkworth
Waiheke Island

All of that on its own is enough to keep you busy for more than 10 days! Waiheke is definitely worth 2 days if you can swing it!