North Korea's test was strongly condemned by Minister for Foreign Affairs Dermot Ahern.
He described it as "a threat to regional security and in direct contravention of the objectives of nuclear disarmament and non-proliferation.
"It runs directly contrary to the will of the international community, as expressed by the UN Security Council, and it also ignores the patient efforts of the DPRK's [Democratic People's Republic of Korea] neighbours to work constructively with it," the Minister said. Mr Ahern called on the DPRK "to refrain from further dangerous acts and to return immediately and without preconditions to the six-party talks".