I think deemed disposition is really for emigrants who are leaving Canada for good. In your case, I don't think you need to do deemed disposition. Maybe you should keep filing tax return in Canada while working in NZ so that when you eventually move back to Canada, you won't encounter problem with CRA asking for unpaid taxes on overseas income! Big accounting firm, like KPMG will give free 1hr consultation so perhaps you can check with some accountants regarding filing taxes working overseas. In our cases, we have declared to be non-residents so we have kept very little money in our Canadian bank accounts so that no T5 is generated. In addition, we notified TD Direct Investing about our non-resident status so that they will deduct 15% withholding tax on all dividends generated from non-registered holdings so NR4 is generated instead of T3. We can't buy anything new from our TD non-resident investment accounts anymore. I don't know if you own a house in Canada or not but if you maintain a primary residence in Canada, then don't think you can claim to be non-resident but I may be wrong.

BTW, NZ is beautiful, I don't miss snow ;-)