Chief Constable Matt Baggott's close working relationship with Garda Commissioner Fachtna Murphy has ruffled a few feathers.
The Chief has described his relationship with the Commissioner as "very close and practical", while the Taoiseach has even described it as "extraordinary".
Within his first week in the job, the Chief travelled to Dublin to meet Mr Murphy, attending a dinner and conference together.
Since then, the two forces' command teams have been attending joint seminars and a senior garda officer has even been seconded to join the PSNI with full powers -- including the right to carry a gun and wear a uniform.
Mr Baggott comes from a policing background where forces working together and sharing resources is the norm.
Crime does not stop at the border and Mr Baggott sees greater co-operation between the north and south of Ireland as the best way forward. Coming to Northern Ireland with no political baggage, his judgment is based purely on policing terms.
But this co-operation and his modern way of thinking has not gone down particularly well in some unionist circles.
One unionist politician said: "Policing here is the responsibility of the PSNI alone.
"Any suggestion of Garda officers having involvement in day-to-day policing here is totally out of the question. It is just totally offensive."
And apparently it is making some 'old school' officers feel a bit uncomfortable.
One said: "There has always been a level of co-operation with the Gards, but the Chief is bringing this into a whole different level and some of us aren't too sure about it. Where will it end?"
However another officer said: "This is the only way forward. The border isn't a barrier for the criminals, so why should it be a barrier for police?
"If we are to tackle everyday crime -- on top of a terrorist threat -- at a time when purse strings are being pulled tight, then we will have to use every means necessary.
"This is modern policing. The Chief is not going to let politics interfere with what is the best way forward for policing in Northern Ireland."
