The British government has urged Ireland to sign up to EU measures which would allow police from the North and the Republic to cross the Border as part of surveillance operations.
Under the measures, members of the Police Service of Northern Ireland and the Garda Síochána could cross the Border between the North and the Republic when involved in the surveillance of suspects.
The Northern Ireland Secretary, Mr Paul Murphy, is understood to have raised the issue with the Minister for Foreign Affairs, Mr Cowen, at a meeting of the British/Irish Inter-Governmental Council in Farmleigh a fortnight ago.
While there has been no substantive response from the Government, the matter is expected to feature in discussions between officials in the New Year.
The Government has not signed up to the EU provisions on cross-border surveillance, or "hot pursuit", of suspects in the past due to the political sensitivity surrounding the prospect of members of the North's security forces operating in the Republic.
However, it is understood that there may now be a greater willingness to reconsider the position in the light of police reform in Northern Ireland. Sources within both governments have confirmed that the matter is the subject of ongoing discussions between them.
The issue arises under the 1990 Schengen Convention, which provides for the abolition of controls on persons crossing international borders. While incorporated into the EU by means of a protocol attached to the 1996 Amsterdam Treaty, Schengen is not binding on EU member-states.
The UK initially remained outside the Schengen system, as it was unwilling to abolish border controls. Ireland followed suit in order to preserve the common travel area it shares with the UK.
However, in 1999, the UK successfully applied to participate in the elements of the agreement relating to law enforcement and criminal justice co-operation. Ireland subsequently applied to participate in the same elements.
One key difference, however, was that while the UK opted into the cross-border surveillance element contained in article 40 of the convention, Ireland did not.
This aspect of Schengen enables surveillance begun in one state as part of a criminal investigation to continue in another. While prior authorisation would normally be required, such permission would not be necessary in emergency situations, during which the surveillance could continue for up to five hours until local police could take over.
According to Government sources, the Irish decision to stay out of this aspect of the agreement arose from political sensitivity over the prospect of RUC officers being involved in surveillance in the Republic.
The UK transposed parts of article 40 into its domestic law earlier this year and will implement other parts through administrative measures. Britain has made it clear to the Irish Government that it would like to see Ireland sign up to this as well.
Since having its application to opt into article 40 accepted, the British government also applied to sign up for the "hot pursuit" element of Schengen, under which police from one state could pursue suspects into another. The British application failed when French objections ensured that it did not obtain the necessary unanimity.
However, British sources say that they would be willing to apply again to participate in "hot pursuit" should the Irish Government seek to join in as well.
Sources in both governments this week emphasised that, even without Ireland opting into any new Schengen measures, cross-border security co-operation was very good. Ms Barbara Roche, the British Home Office Minister, told the Westminster Select Committee on the EU 12 months ago that, "given the nature of the United Kingdom/Irish border within the Common Travel Area, there has been highly-developed co-operation for many years of the sort which Schengen provisions are designed to address".