UN Secretary General Ban Ki-moon has paid tribute to Ireland's contribution to UN peacekeeping missions over the past 50 years.

Mr Ban is on a two-day official visit to Ireland and met the Taoiseach at Government Buildings for a working lunch before addressing the Joint Oireachtas Committee on Foreign Affairs.

Mr Ban paid tribute to the 90 Irish citizens who lost their lives during UN missions.

'I pay tribute to your fallen personnel. And I express my deepest appreciation to Ireland for its long-standing commitment to these operations.'

The UN Secretary General also addressed members of the Institute of International and European Affairs at Dublin Castle this morning.

He also said he hoped Ireland would keep the UN central to its foreign policy agenda.

After meeting the Taoiseach, he said the UN would spare no effort in providing the necessary support to help secure the release of Sharon Commins.

The GOAL aid worker from Dublin was kidnapped in Sudan last week.

Mr Ban said the UN would continue to provide the necessary support in terms of information and logistics on the ground to help ensure her safe return.

The Secretary General met with Environment Minister and Green Party leader John Gormley.

They discussed the issue of climate change ahead of the Copenhagen summit.

Mr Ban will meet Minister for Defence Willie O'Dea and the Army Chief of Staff tomorrow to discuss Irish participation in UN-mandated peace operations.