The union said it had engaged in contacts with various parties in recent days to resolve the dispute which has seen 32 workers encamped in the foam plant on the Kinsale Road for almost 80 days.
Among those parties was employers’ body Ibec which was acting on behalf of Vita Cortex.
The union said it had made it clear to Ibec that the workers would not end their sit-in until they were given 0.9 weeks per year of service by the employer.
Siptu manufacturing division organiser Gerry McCormack said IBEC contacted him yesterday with what he described as a “derisory offer” of less than half of what he described as “the agreed redundancy amount owed to the workers”.
The claim of the workers is valued at €372,000, but it is understood the offer made by the company through Ibec was just over €185,000.
“It was an insult to our members who have been enduring extremely harsh conditions during their occupation of the plant for almost 80 days,” Mr McCormack said.
The union said the workers had been informed of the offer at a meeting and they endorsed the Siptu position that the offer was unacceptable and that nothing less than the full 0.9 weeks per year of service would resolve the dispute.
“They are also very angry at the manner in which they and their union representatives have been treated during these latest discussions,” Mr McCormack said.
“The employer and Ibec need to demonstrate that they are prepared to act in good faith and to honour what are basic principles of decency in the treatment of these workers.”
Last night a spokesman for Vita Cortex said it would be issuing a statement in the next 48 hours on what was offered to the staff and what it requested from them.
The 32 staff at the heart of the dispute lost their jobs when the plant shut down on December 16 and have been occupying the building since in pursuit of the 2.9 weeks per year of service redundancy package which they say the company paid to previous employees.
The State has since covered the two weeks’ statutory payment. The workers say company owner Jack Ronan must pay the remainder.
Mr Ronan, employers’ group Ibec and Vita Cortex director Seán McHenry have all denied the ex-gratia payment was ever promised.
The protest has attracted attention from almost every public spectrum.
Among those who have voiced their support for the workers are Manchester United manager Alex Ferguson, Hollywood actor and fellow Corkonian Cillian Murphy and musicians John Spillane and Christy Moore. Former President Mary Robinson and US intellectual Noam Chomsky have also publicly backed their plight.