Liam Kelly was reacting to the news tonight that a new chief constable had been appointed.
As well as the funding issue, Mr Kelly said “most of all, our officers want to know their Chief Constable has their back”.
In a statement on Tuesday night, he said: “The list of what must be fixed is long and can only be addressed by a meaningful and realistic funding package from Government.
"Taken together, the service will need a commitment to invest up to £500 million.
“There’s a worrying funding gap coupled with the cost of the data breach and officer holiday pay which account for most of what’s required.
"There’s no recruitment and serving officers are leaving because of the pressures they endure in doing their job.
"If the government doesn’t step in to deal with chronic and deep-rooted challenges, we will see officer numbers shrink to 6,000 and that is unsafe and unsound.
“[The new chief] knows what has to be done to restore balance.
"Getting Ministers to realise and then fix the parlous state of the PSNI is the main priority.
"That will require intensive lobbying at Whitehall as NIO ministers don’t seem to care and have turned a deaf ear to policing requirements.
“Internally, it will be important to re-build confidence and morale. Disciplinary processes are in need of reform with far too many officers waiting an inordinate length of time for cases to be resolved.”