Labour Party leader Mr Ruair∅ Quinn told SIPTU delegates he supports their claim for higher statutory redundancy payments in the face of closures and cutbacks in staffing sweeping the state.
Mr Quinn said the 1977 redundancy legislation had been "very parsimonious", even by the standards of the time.
At present workers are entitled to half a week's pay for each year of service up to 41 years of age and one week's pay for each year after that. SIPTU is looking for at least three weeks pay for each year of service, regardless of age.
The Labour Court often awards higher redundancy payments but the decisions are not binding. Mr Quinn said it was "not sufficient any more to rely on Labour Court recommendations" when some companies ignored them.
"For that reason our intention is that the baseline legislation be brought into line with Labour Court practice."
The new general secretary of the Irish Congress of Trade Unions, Mr David Begg, said SIPTU held a special place in the history of the labour movement since the days of the 1913 lockout. The 1916 proclamation was printed in the basement of Liberty Hall.
"The brutal fact is that to retain our industrial strength - and our legitimacy to speak for workers - we must make recruitment and organisation our priority. Unfortunately, the case for collective bargaining has to be argued from first principles to every generation of workers," he said.
"It is a constant struggle. However old-fashioned it may appear to say it, the struggle between capital and labour is an enduring one" and "the sheer mobility of capital has made the struggle, if anything, more difficult."
Unions were "the only actors in the market system capable of effecting redistribution of wealth and some social justice". While the "AA model" of trade unionism offering members credit cards and discount shopping had its place, this approached "opts into consumerism, while opting out of the moral content of solidarity and social justice that has been the core of union history".
The movement had a "moral agenda" it must pursue, said Mr Begg. Beneath rapidly changing technological change, "the soft human resource management techniques and the glitz of modernity" a lot of people were as exposed as ever to the "hard brutalities" of the labour market.
"This is why I think we should tell it as it is and stand or fall by the integrity of our message. I would like to see us becoming a more overtly campaigning movement making alliances with other civil society organisations that share our values. We should put a bit of effort into expanding our mission of social cohesion," he said.
"Remember that the main reason people don't join unions is that they have never been asked."