The refusal of the Executive to give the National Crime Agency (NCA) police powers here could leave a black hole in the PSNI budget, it has been warned.
UUP peer Lord Empey said it raised fears that important areas of organised crime would not be dealt with adequately.
The cost implications are being looked at by the Stormont Justice Ministry. In a written answer to UUP MLA Tom Elliott, Justice Minister David Ford said: "Officials are chairing a group with representatives from law enforcement agencies and others, to assess and address the gaps created by the inability of NCA to provide support operationally or as a result of the restrictions on its civil recovery activity. There are, for instance, legal and resources issues to consider."
As things stand, the NCA will be able to operate in areas like customs and immigration because they are not devolved powers and are outside Stormont's control.
The most serious gaps left are in fighting gangs with a UK-wide or international reach in areas like child exploitation, fuel laundering, people trafficking, drug dealing and cybercrime.
At present, these national responsibilities are covered by the Serious and Organised Crime Agency (Soca), which has the power to operate here but is currently being wound up. Stormont has effectively blocked the NCA from taking over Soca's role anywhere it has power to do so.
The working group is seeking ways for the NCA to share intelligence with the PSNI and co-operate closely.
However, the NCA will not have powers to carry out searches, make arrests, conduct surveillance operations or recruit informants here without Stormont's say-so, and that could create blind spots in UK-wide investigations. There would be problems if NCA informants from outside Northern Ireland were used here, especially if they were needed as witnesses in court or arrested by the police.
Lord Empey warned that such loopholes could lead to us becoming the "preferred operating base" of international gangs who might prefer to face a regional police force rather than a national agency. Northern Ireland would be even more attractive to gangs because of our border with the Republic.
Lord Empey said: "Like the FBI in America the NCA will have a national expertise in crucial areas. If the PSNI tries to carry out NCA functions itself, that would be challenging in practical terms.
"It would have to somehow replicate the NCA's expertise and that would cost money. I am convinced Westminster won't make up the shortfall for us because the problem is a result of the Executive's decision to opt out of a national agency. There is no way that we will get extra funds."
Story so far
The National Crime Agency (NCA) is a new FBI-style body formed to fight "serious, organised and complex crime" across the UK. It replaces the Serious and Organised Crime Agency. In February, a Stormont petition of concern by nationalist parties prevented the NCA from having police powers here. They argue it would not be locally accountable. This means it will not be able to operate independently here in areas like fuel laundering and people trafficking, leaving the PSNI to carry the can.