You need to make friends with the Immigration NZ website - be prepared to take your time understanding all the steps on the VARIOUS possible routes. Everything is pretty complicated, and it takes a while to get the head round what people are talking about. Use the Search for old threads on anything that puzzles you - you may well find you're not the first person with a question on that point.
You cannot get a work visa unless you have job offer. Here's where to start looking for the information about work visas of various sorts, and/but follow the links to make sure you see all the details.
http://www.immigration.govt.nz/migra.../requirements/
If you are well enough qualified and experienced in a skilled line of work, you may possibly be able to apply directly for Residence under the Skilled Migrant Category
http://www.immigration.govt.nz/migra...nt/default.htm without having a job offer first, but be aware that the way the quotas are running at the moment, no EOI with a points total below 140 has been selected for a long time. Those with at least 100 points and a job offer do get selected at once, though.