Irish Congress of Trade Unions General Secretary David Begg has questioned the Government's new pension plans.
The plans propose to increase the retirement age and introduce a mandatory scheme for all workers.
Speaking on RTÉ's Morning Ireland, Mr Begg said it was wrong to entrust payments to Irish pension funds, saying they have been the worst performing in the developed world.
Aspects of the plans have also been criticised by employers' group IBEC.
It said that paying 2% towards employee pensions would mean employers having to find the money elsewhere, through pay cuts or productivity savings.
However, IBEC supported the move to increase the State retirement age to 68 by 2028.
The Government said it is introducing the reforms to address problems regarding population changes, income adequacy in retirement and to ensure the sustainability of its finances.