The police had argued the so-called Complex Investigation Phased Engagement Model should not be made public because of the risk it could be misused by untrained investigators or make suspects suspicious.
The media organisation Stuff took legal action, arguing it was in the public interest to be able to scrutinise police conduct in the case.
In revoking his suppression order, Justice Simon France agreed there was "legitimate public interest in querying a specialist interviewing model that's been poorly used".
"Numerous breaches of several rules were identified, and it is legitimate to query the correctness of the underlying method."
Furthermore, the technique itself merited public scrutiny, he said.
"It is a method that has the effect of downplaying, or arguably obscuring, the true nature of what is occurring. Mr X was a suspect in a murder who was being interviewed because the police had information implicating him.
"Yet an environment is created where what seems almost a fireside chat occurs. There are none of the typical trappings of a suspect interview.
"Whether this is legitimate or desirable is not for the Court at this moment to comment on; it is something, however, that merits discussion."
The rules on interviewing criminal suspects were long established and compliance was "necessary and expected", he noted.
"The consequences of untrue admissions are often dramatic and a source of miscarriage."
