Minister for Foreign Affairs Dermot Ahern today said the Lisbon Treaty was Ireland's best hope as a small country to have its say in the international community on issues such as globalisation, climate change and the developing world.
Mr Ahern was urging a Yes vote for the treaty, as both Sinn Féin and one of the country's largest trades unions, Unite, opened their campaigns for a No vote.
"The Treaty will strengthen, empower and boost this country," Mr Ahern said.
Jimmy Kelly, Unite
"The bottom line is that the challenges facing Irish jobs and Ireland's environment and Ireland's competitiveness today are global," he told the Institute of European Affairs.
"The European Union now needs the Reform Treaty if it is to continue delivering benefits for us."
Unveiling Sinn Féin's national campaign to oppose the treaty, MEP Mary Lou McDonald called for a mature debate on its consequences for the country.
"This treaty is a step too far and is a bad deal for Ireland. The referendum will have huge consequences for this country and it is important that there is a mature debate," she said.
Sinn Féin claims the charter gives the EU too much power and reduces the State's ability to stop decisions that are not in Ireland's interests.
The Unite trade union also announced it will campaign for a No vote in the Lisbon Treaty referendum.
The union, which claims to be Ireland's second largest, said today it will encourage its 70,000 workers in the Republic to reject the treaty.
Unite regional secretary Jimmy Kelly criticised what he said was the Government's lack of action on workers' rights and "its seeming desire to railroad the treaty through without providing commitments on what it will mean".
"Our role is to look out for the rights of our members. This Government is full of empty promises and sleight of hand when it comes to dealing with the issues that matter to workers," he said.
Mr Kelly criticised the Government's opposition to Europe on the Agency Workers Directive, "which is a cornerstone of fair treatment for the lowest paid and least regarded workers in Ireland".
"They ignored the Supreme Court ruling in the Ryanair case on rights to representation, leaving workers exposed in a similar manner to that which was the case 100 years ago. They buried their heads over mandatory pensions, ignoring the fact that one million people are heading towards poverty in old age."
Mr Kelly said rejecting the treaty "will make it crystal clear that we need to see concrete evidence on workers' rights, not just empty promises".
Elsewhere, the National Forum On Europe will begin a series of public meetings around the country tonight with guest speakers both for and against the treaty.
The inaugural meeting will be held in Blanchardstown Public Library with Ruairí Quinn, chairman of the Alliance for Europe, campaigning for a Yes vote in the referendum and Socialist Party leader Joe Higgins, who is against the Treaty.
Other members of the National Forum On Europe, who represent all the political parties and leading national organisations, are expected to attend.
Additional reporting: PA