Just as the Government faces renewed criticism about its ability to protect private information, it is proposing to allow Inland Revenue to share taxpayers' information with law enforcement agencies.
However, Revenue Minister Peter Dunne says protecting tax secrecy remains a top priority.
Under the proposal, the tax department would pass on confidential information about taxpayers to police and other agencies in cases involving serious crime.
Mr Dunne said Inland Revenue holds certain information such as income, tax history and business connections that could help other government agencies investigating serious crimes. But he says there would be clear restrictions to protect privacy.
He told Radio New Zealand's Checkpoint programme on Tuesday that, at times, Inland Revenue has had information that could have assisted police investigations.
"There have been occasions when that's been the situation, and it's frustrating for both agencies when you know on the one hand what assistance you might be able to offer.
"But we're looking here at very serious time - we're not about the more run-of-the-mill crime. We're looking at where there's a threshold of at least a four-year prison term involved."
Police Minister Anne Tolley said people have nothing to fear if they are not committing serious crimes.
The Labour Party's revenue spokesperson David Cunliffe says the Government needs to be careful, given the series of privacy breaches among its agencies.
The Government is seeking public feedback on the proposals. Peter Dunne said people can have their say online and respond to five scenarios showing how Inland Revenue might share information.
The proposals make it clear that the information can be shared only when serious crime is likely to be uncovered. Public consultation ends on 21 May.