The leadership and commitment shown by Siptu through the years will be crucially important as the country battles the worsening economic crisis, President Mary McAleese said tonight.
At the union's centenary celebrations, Mrs McAleese said Ireland once fought to escape from poverty but is now fighting to hold on to prosperity.
She paid tribute to the trade union movement, which she said played a significant role during the Easter Rising and in the early years of the state.
"The leadership and commitment shown by Siptu representatives over many years has been crucial and will be crucially important as we face together into the economic storms that beset Ireland and much of the world," she said.
"The short-term prognosis is not a pretty sight but this union has endured and survived much worse in its 100 year history. Usually Ireland has been fighting to escape from poverty now uniquely for us we are fighting to hold on to our prosperity."
The union held a night of celebrations at Liberty Hall in central Dublin to mark the anniversary.
Speeches were given by general secretary Joe O'Flynn and general president Jack O'Connor, while music was also provided.
A look back over the union's history was also given by Labour historian Francis Devine.
Ms McAleese paid tribute to the social partnership model, formed in the recession-hit 1980s, and in which the union played a significant part.
"It broke us out of a paralysing cycle of confrontation and blame and created a remarkable momentum as the diverse interest groups that make up our society united to create a consensus from which all would benefit," the President said.
Ms McAleese said she hoped the public, inspired by the "altruism" behind the union, would dedicate itself to forging a state where all the children of the nation are cherished equally, as envisaged in the 1916 Proclamation.
"It's the work this union has promoted for a century," she said.
Siptu was established in 1990 with the merger of its two founding Unions - the former Irish Transport and General Workers' Union and the Federated Workers' Union of Ireland.
However it traces its lineage back to the early years of the 20th century when Jim Larkin began organising among the transport and dock workers of Dublin.
The union now represents some 200,000 workers from virtually every category of employment from throughout almost every sector of the economy.
PA