You can read about the NZ program at http://www.dfait-maeci.gc.ca/asia/whp/canada-permit-en.asp Looks like you have to be between 18 and 30 and you'll get a permit for one year. The UK program looks pretty much the same, see http://www.bunac.org/uk/workcanada/eligibility.aspx
You should contact both programs, ask them about available space as well as cost and then decide.