The Inland Revenue Department is to go public about its controversial power to search business premises and private homes in the hunt for tax evaders.
Under section 16 of the Inland Revenue Act, investigators have the right to arrive unannounced at a business or home and to enter it, search for and take away material.
There were about 40 such searches during 2012.
The IRD says section 16 has attracted criticism in the past and a number of disputes have been to court.
Its group tax counsel Graham Tubb says it will issue an operational statement in a few weeks' time sopeople understand they have to allow investigators entry and co-operate with requests for things like computer passwords.
"What the legislation says is that the occupiers of the premises need to give reasonable assistance to enable the examination of those documents and also to answer proper questions in the course of a search, for example what is the password to that computer, where is the key to that cabinet - that kind of thing."