Amnesty International has described as "a huge victory for human rights" the adoption by the United Nations of a historic treaty limiting the trade in conventional arms.

The treaty lays down clear rules governing the transfer of weapons on a global level.

It requires countries to ensure that arms cannot be used to carry out war crimes or other human rights violations.

The arms transfer cannot go ahead if there is a real and substantial risk of war crimes being carried out.

Speaking on RTÉ's Morning Ireland, Amnesty Ireland Chairman Colm O'Gorman said it marked the end of 20 years of campaigning by Amnesty International and other groups to achieve regulation of the international trade in weapons.

The treaty opens up for signatories at the UN general assembly from June.

It comes into force once 50 countries have ratified it.

The states involved will then monitor its implementation.

Tánaiste Eamon Gilmore has signalled that Ireland will ratify the treaty as soon as possible.

Mr O'Gorman said the treaty was now the new international norm for the transfer of weapons and it set the standard for countries to follow.

He said he believed it would result in new rules governing the trade in arms being developed at national level, and the strengthening of rules in countries that currently do not have any national law about the transfer of weapons.

Mr O'Gorman said that while winning agreement on the treaty was a massive battle, it would be another huge fight to get it implemented.

The global arms industry is worth $100 billion (€78bn) a year.

Mr O'Gorman said that while winning agreement on the treaty was a massive battle, implementing it was the next major battle.