Minister of State for Development Joe Costello said it had been hoped the US would sign the first treaty to regulate the $70 billion (€53.6 billion) global arms trade at a ceremony in New York yesterday.
Sixty-seven countries, including Ireland, signed the UN Arms Trade Treaty yesterday, Mr Costello said, but the US, the world's number one gun manufacturer, was not among them.
The US is awaiting all official UN translations of the treaty before signing, the US secretary of state John Kerry said in a statement.
Mr Costello, who signed the treaty on behalf of the Irish Government, said the US signing the treaty would have been "a signal in the right direction", but he acknowledged it was a "big issue" for the US because of the gun control debate domestically and because the country is a major weapons manufacturer.
“The expectation is the US will sign up to it,” he said. “There may be some difficulty with ratification, but they will sign up to it – [that] is the general expectation. There was a hope they would have signed up to it [yesterday].”
The treaty will enter into force 90 days from now given that 50 nations have ratified it.
The 193-nation UN General Assembly overwhelmingly approved the treaty, which aims to take weapons away from human rights abusers and criminals.
The junior minister Mr Costello will meet the UN's under secretary-general for humanitarian affairs Valerie Amos at a meeting this morning to discuss the humanitarian situation in Syria and Mali.
Mr Costello blamed the absence of any active engagement among the UN security council and the main players in particular, the US, Russia and China, for the dragging-on of the two-year conflict in Syria.
“We have reached the stage where even now it is going from bad to worse,” he said.
The Minister of State described the job facing Mary Robinson, the UN's special envoy for the troubled Great Lakes region of Africa, as a "huge task".
Mrs Robinson, a former Irish president and UN high commissioner for human rights, will in March give her first public address to a UN audience in New York since being appointed special envoy.
The Minister will join her in a panel discussion on women and peace-building in the Great Lakes region, which has been ravaged by years of violence leaving more than 5.5 million people dead.
Mr Costello said Mrs Robinson was looking at social problems within the Democratic Republic of Congo and the role of women and human rights to build on a peace accord signed by leaders in the region.
