I think this answers you question;
"Evidence students without a job offer must supply
"If you are applying under our Study to Work Category but you do not have a job offer, you will be applying for a Graduate Job Search work visa for up to 12 months. You must provide:
evidence that you have successfully completed a qualification in New Zealand that would qualify for points under the Skilled Migrant Category of Residence Instructions
evidence that your application for a work visa has been lodged no later than three months after the end date of the student visa for that qualification
evidence of a minimum of NZ$2,100 available to maintain yourself during your 12-month stay in New Zealand (we will accept traveller's cheques or bank documents in your name)."
here's the link;
http://www.immigration.govt.nz/migra...y/studytowork/