Hi Cath,
Don't believe the "You need a work permit" statements.
It's true but misleading.
Once you get a job offer you can apply for a work permit.
That can take days, but could take maybe weeks (or more !).
The statement is to deter those not in NZ, and because it's not so easy and quick for the agencies.
They'd prefer to get their money quickly.
You need the work permit FIRST, before you work. No doubt on that one.

Don't forget that if you get a visitors visa (rather than just visiting) you may be able to stay for a lot longer.
You need to check for your country. I don't know where you are.
If you check the NZIS site on holidays you'll see that it's 9 months in every 18 months.
But it's a bit more complicated than that.
Have a look at my website. You might find some useful answers.
My wife and I & kids are hoping to emigrate within the year.
My website just lists everything I've learnt about it.
Then please come back and ask away !
It's Taffy's site, and he's very knowledgeable (OK Taffy !)

I hope that helps.

Steve