Now, this is interesting:
The Ontario Court of Appeal has recognised a right to privacy in personal information stored on work computers. Although the facts in the case are a bit peculiar and Canada case law is not directly applicable to New Zealand, it can and might have some persuasive weight in cases over here.
What the court said was essentially that employees are protected from unreasonable search and seizure under section 8 Canadian Bill of Rights (which equals section 12 Bill of Rights Act NZ) and that a constitutional right to privacy exists where an employer let employees use its electronic devices for personal purposes.
Interestingly, in another Australian case, Griffiths v Rose & Ors  FCA 30 (31 January 2011), the Federal Court held that the monitoring by a government department of its employees’ personal use of IT system, does not constitute an invasion of privacy so long as the employee is informed that such surveillance may occur.
So, two cases, two completely different outcomes. Not much help.