The UN's legal counsel has rebutted allegations that the International Criminal Court (ICC) is applying 'selective justice' by concentrating its attention on Africa.

Patricia O'Brien also described as a 'misconception' claims that the US is 'in combat with' the court because it has not signed up to the decade-old institution.

O'Brien, under-secretary-general for legal affairs at the UN, oversees the organisation's 200-strong Office of Legal Affairs. She was interviewed at the IBA conference in Dublin today, where debate focused on the UN's inaction in Syria and the allegedly pro-western bias of the ICC.

O'Brien was pessimistic about breaking the continuing deadlock among the five permanent members of the UN Security Council on dealing with the civil war in Syria, a situation she described as 'paralysis'.

In July, Russia and China vetoed a Security Council resolution on Syria calling for further sanctions, prompting anger among the western members. 'Inaction is intolerable, but we have to tolerate it,' she declared, observing: 'The UN charter is our constitution and the veto is entrenched in it. Until the member states decide to change it, the law is as it is.'

When asked whether the Security Council is 'fit for purpose', she admitted efforts at reform 'have got nowhere'. O'Brien advised on a failed draft resolution earlier this year from the so-called 'Small five' group of nations - Switzerland, Costa Rica, Jordan Liechtenstein and Singapore - to include non-permanent members more closely in its deliberations.

O'Brien stressed that promoting the establishment of the rule of law in nation states is 'critical' to inhibiting regression to crimes against humanity. 'If a society is founded on the rule of law, the likelihood of such a degeneration is slim,' she said.

She remains confident justice will prevail in Syria. 'The shadow of justice is hanging over the perpetrators of war crimes [there],' she said. 'There will be a day of reckoning.'

Commenting on the ICC, O'Brien admitted that international justice is 'both expensive and slow' - the court did not deliver its first verdict until March this year, finding Congolese warlord Thomas Lubanga guilty of recruiting child soldiers.

But she stressed that the court is both young and evolving, adding: 'We are only at the beginning.' She also dismissed the suggestion of one inquisitor that the court's credibility is fatally compromised because the US is not a signatory and there is no prospect of bringing George W Bush and Tony Blair to trial for alleged war crimes in Iraq.

'Accusations of "selective justice" have been rife since the establishment of the ICC,' she said. 'The court is reviewing seven situations in Africa, but one must bear in mind that [all but two] were self-referrals.'

She added: 'The US is not a party to the Rome statute [which established the ICC] but it cooperates extraordinarily in many ways and supports the court's work. It is a misconception that the US is in combat with the court.'