ICTU general secretary David Begg has described the decision to abandon social partnership agreements between unions and employers as a "mistake" in his first ever address to the Seanad.
As the head of the umbrella body for 800,000 workers, he was invited in by the Seanad to reflect on the 100th anniversary of the 1913 Lockout and its implications for modern day politics.
And he also highlighted the fact that the social partnership process which led to agreements between employers and unions had not survived the economic crash in 2008.
"In time, I think this will be seen as a public policy mistake," he said.
Mr Begg complained about the fact that workers still did not have a legal right to have a union negotiate on their behalf 100 years after the Lockout.
Seanad Cathaoirleach Paddy Burke said that the rules of the Seanad had been changed to allow people in civic life like Mr Begg to address it.
"This Seanad is determined to modernise its procedures," he said.
However, it comes as voters are being given the choice on October 4 of abolishing the Seanad.