A director of the business organisation IBEC has accused SIPTU of posturing and causing uncertainty over social partnership.
Brendan McGinty said that the public was tired of SIPTU's posturing and setting of pre-conditions.
He called on the union to make up its mind whether or not it was in favour of social partnership.
Mc McGinty also accused SIPTU of in indulging in 'exaggerated commentary and claims, unsupported by independent research, about the treatment of migrants and the displacement of Irish workers.'
However, SIPTU's General President Jack O'Connor has hit back at the IBEC criticism.
He said it did not stand up to scrutiny and he cited the GAMA and Irish Ferries rows as issues raised by SIPTU that were not unfounded.
Mr O'Connor also said that the IBEC director's comments were 'hardly conducive to creating the conditions for reviewing the Towards 2016 agreement.'