The Employment Relations Authority has delivered a stinging rebuke to the Defence Force for refusing to bargain over pay with unionised civilian workers.
The decision follows months of tense negotiations between the Defence Force and the Public Service Association, and two strikes in April.
In the mid-2000s, the Defence Force started offering some unionised civilian workers, like cooks and security officers, individual employment contracts.
While many elected not to sign up, a large number took the higher wages offered.
PSA national secretary Glenn Barclay said the organisation had tried to undermine union support.
"The employer basically chose to pay people on individual agreements more than those covered by the collective agreement [with the] clear intent to discourage new workers from joining the union."
By 2010, enough workers had signed individual contracts that new negotiations created two types of employees among unionised workers.
Those who had signed individual agreements could keep their higher salaries, but in return they lost their right to negotiate future pay increases.
It also meant they were cut out of any pay rise negotiated by the union.
Many of those workers regretted signing up to the deal and wanted to reclaim the right to bargain, the PSA said.
Mr Barclay said the Defence Force had flat-out refused to consider it when he approached them last year.
"We wrote to the Chief of Defence advising him that he was required as a matter of law to bargain pay, and to request his confirmation that Defence would bargain pay, but [he] stuck to their line that they had the right to issue orders to set pay."
The armed forces have the final say on how military personnel are paid under the Defence Act, but civilian workers are covered by the Employment Relations Act, which requires both employers and workers to enter into collective pay talks in good faith.
The PSA went to the Employment Relations Authority, seeking a ruling on whether the Defence Force was obliged to consider wage negotiations under the collective agreement.
In his ruling in September, the Authority's presiding member Mike Loftus was clear.
"Civilian workers are covered by the Employment Relations Act and have the right to bargain collectively and periodically about all matters - including wages," the ruling said.
"The very nature of bargaining means the PSA is entitled to propose either a change or the complete removal of a clause. NZDF cannot simply say it will not agree to the inclusion of a scale."
Mr Loftus ordered the Defence Force to negotiate meaningfully with the union over pay, and chided the government department for its inaccurate interpretation of the PSA's arguments.
RNZ sought comment from the Defence Force about the case, the justification of its actions, and whether it would abide by the ruling or appeal it.
In reply, a spokesperson issued this statement: "We have received the decision which we are considering. We have no further comment."
The PSA will hold further talks with the Defence Force early next month.