The Police Federation has won High Court permission to challenge the decision to press ahead with axing full-time reserves.
Leave to seek a judicial review was granted over claims that former Chief Constable Sir Hugh Orde failed to consult with the organisation before confirming the unit was to be phased out.
Lawyers for the officers' representative body want a new process to be undertaken because they claim Sir Hugh's security review was flawed by non-consultation.
Up to 400 remaining Full Time Reserve (FTR) officers are to leave the PSNI by March 2011, with front-line duties ceasing by next summer.
Barrister Peter Coll, for the Federation, argued that the announcement in June amounted to a fresh decision, even though police chiefs previously declared the reservists were to go.
He said: "There was a custom in practice over an extended period of time that the Police Federation would be consulted by the Chief Constable in advance of decisions of this nature, particularly major personnel decisions.
"They were excluded from that process in 2009. It flies in the face of the previous conduct, it flies in the face of the legitimate expectation arising from that previous conduct, and it flies in the face of rationality."
"The process the Chief Constable used to reach his further decision was flawed. He didn't consult with the Police Federation."
Tony McGleenan, for the Chief Constable, countered by claiming Police Federation chairman Terry Spence made no complaint about lack of consultation in correspondence with the Policing Board.
Ruling on the application for leave to seek a judicial review, Mr Justice Weatherup held that although no new decision was reached in June, there was the potential for one.
"There was, I'm satisfied, a prior practise of consultation in previous reviews," he added.
Although he granted leave on that ground, Mr Justice Weatherup rejected a second part of the challenge based on claims that the decision failed to take into account the security situation.
The case will now proceed to a full judicial review hearing in November.
© UTV News