Some possible safeguards have been left out in proposed legislation under which private companies could get access to taxpayers' personal information.
The Privacy (Information Sharing) Bill reduces the threshold under which information can be disclosed if there is a risk to public health and safety or threat to the life or health of an individual.
It also allows the sharing of personal information between agencies if done in accordance with approved information-sharing agreements.
That could include disclosure to private firms or non-governmental organisations as well as between government departments.
Privacy Commissioner Marie Shroff said technological advances had made it easier to share information but without proper safeguards the Government risked losing New Zealanders' trust.
There were a number of "finely balanced" safeguards in the bill, but Ms Shroff said she would welcome more.
Private organisations were increasingly involved in the provision of public services and the line between public and private sectors was now "very thin".
"It's certainly an issue as to whether business should be allowed some access [to Government-held information] to a limited extent.
"That's exactly one of the concerns we have about this whole technology environment and the trend to use it and share it more widely, that it's the beginning, potentially, of a slippery slope."
Ms Shroff would be monitoring developments and making sure proposed sharing agreements were appropriate.
In its original review, the Law Commission made several recommendations that have not been adopted, including giving the privacy commissioner the power to conduct information audits and issue compliance notices.
Labour MP Charles Chauvel said he was concerned that not all the recommendations were adopted.
Civil Liberties Council spokesman Batch Hales was concerned, but not surprised, about the proposed legislation.
"Government is becoming more and more intrusive into people's privacy and closing out the public in all sorts of ways."
- The Dominion Post