State investigators charged with probing alleged Garda wrongdoing have accused the force of not co-operating with them.
The Garda Ombudsman said it had no option but to go public with its frustrations over "unacceptable" delays and the refusal of officers to hand over documents crucial to their inquiries.
Simon O'Brien, chairman of the watchdog, suggested the behaviour of the Garda would not be tolerated within police forces in other countries.
he said; "I was senior police officer in London's Metropolitan Police, I was there for 32 years. Certainly if a request for information came to me from the IPCC (the UK's Independent Police Complaints Commission) ... then boxes of documents would be handed over in the morning to IPCC investigators."
Signalling a deepening of the fall-out between the Garda Ombudsman and the force, Mr O'Brien said he had been having top-level talks over the past year-and-a-half which has still not resolved the lack of co-operation.
The watchdog said he would not have gone public if the problem was not wide-scale, adding it was clear there were "systemic" issues within the force which have stymied the Ombudsman's work. He said: "We are just not getting the co-operation we require. The numbers speak for themselves."
The Ombudsman's annual report reveals a number of cases where the Garda refused to hand over documents, gave only limited access to files or delayed giving any requested details. On one occasion, it was forced to wait 542 days for a piece of information to be handed over during an inquiry.
Mr O'Brien said the watchdog has powers to enforce its role, and warned while it would rather not arrest officers or raid Garda stations, such action was possible in the future. He said: "I do not wish to be sitting on this platform again next year saying things have not improved."
Garda Commissioner Martin Callinan accepted there were delays in handing over information and added he has set up a new office and email address to deal with Ombudsman requests. The police chief said this was a significant investment of resources at a time when the force was suffering austerity cutbacks.
Mr Callinan added that wider discussions were also going on between the Garda and the watchdog about new protocols for the timely handing over of information to investigators probing alleged wrongdoing. He said: "Substantial progress has been made towards reaching agreement."