The willingness of US prosecutors to pursue business crime suspects living abroad and the recent US extradition proceedings against the "NatWest Three" in Britain may be a worry for Irish directors and executives doing business in the US.

Although most successful companies and executives make every effort to comply with local laws, business conduct which they believe to be legal may subsequently result in criminal proceedings in a foreign state where prosecutors allege that their country's laws were infringed.

The extradition arrangements between the Republic and the US are similar in many respects to those between the US and Britain. However, some important differences in Irish law may help in challenging a request for extradition in the Irish courts.

In the NatWest Three case, the executives unsuccessfully argued that as they and the alleged victim bank were based in Britain and most of the alleged conduct occurred in Britain, extradition should be refused.

In another case, where the British high court refused to block extradition to the US, the US authorities alleged that the British executive had been party to a conspiracy in Britain to operate a price-fixing cartel in the US.

The executive unsuccessfully argued in the British court that at the time of the alleged conspiracy, no equivalent offence to price-fixing existed under British law.

Extradition between the Republic and the US is governed by a treaty agreement between the two countries. This treaty defines an extraditable offence as one punishable under the laws of the Republic and the US by imprisonment for more than one year or by a more severe penalty. This is known as the principle of dual criminality. It must be established that the acts complained of amount to a criminal offence in either jurisdiction.

The Irish courts, when interpreting dual criminality, look at the factual components of the offence specified in the warrant, regardless of the name given to it, and see if those factual components, in their entirety or in their near entirety, would constitute an offence of similar gravity in the Republic.

Under the treaty, however, the US does not have to demonstrate a prima facie case against a suspect when seeking extradition from the Republic.

In contrast, the Irish authorities when seeking extradition in the US, must demonstrate reasonable grounds for believing that an offence has been committed and the person sought committed it.

This imbalance also exists in the extradition arrangements between the US and Britain.

However, in contrast to those arrangements, the Irish-US treaty provides that extradition to the US may be refused when the offence for which extradition is requested is regarded under Irish law as having been committed in Irish territory.

If extradition is refused pursuant to this provision, the Republic is obliged to submit the case to its competent authorities for the purpose of prosecution.

The treaty offers some further comfort for Irish residents as extradition may be refused where the competent authorities in the Republic have decided to refrain from prosecuting the person whose surrender is sought for the offence for which extradition is requested, or to discontinue any criminal proceedings which have been initiated against that person for that offence.

If a NatWest Three scenario arose in the Republic, these provisions would entitle the Minister for Justice, Equality and Law Reform to exercise his discretion to refuse to extradite the executives if they concluded that such refusal was justified.

Even if the Minister declined to exercise such discretion, the executives could draw some comfort from the human rights protections under the Irish constitution and under the European Convention on Human Rights as implemented under Irish law.

The executives would probably argue in the Irish courts that it is unfair that the US authorities are not required to show a prima facie case when seeking extradition from the Republic.

Although this argument did not succeed in a case in 1984 under similar arrangements between the Republic and the UK, the executives could also seek to persuade the court that they would face hardships in the US that would over-ride their human rights under Irish law.

Like the NatWest Three, they might point to a likely lengthy delay before trial in a jurisdiction thousands of miles from the Republic, prison conditions that may be harsher than those in Irish prisons, and exposure to mandatory sentencing regimes that exist in some US states.

It should be stressed that the Irish courts would be slow to block extradition on human rights grounds where the extradition request satisfied other relevant criteria under Irish law.

This is because extradition arrangements exist for the mutual benefit of the systems of criminal justice in treaty states.

It is likely, therefore, that the success of any application would depend on whether the court was satisfied the executives' human rights concerns were serious.

•Roddy Bourke is a litigation partner in McCann FitzGerald solicitors Dublin