Workers at Bord na Móna Recycling, who are members of SIPTU, have met with opposition politicians at Leinster House to voice their concerns over the proposed sale of the business.
SIPTU has called for a halt to the sale, claiming the move is counter to economic and environmental best practice.
Last week, the union's members employed in the recycling business voted to conduct a ballot for strike action if plans to privatise the company went ahead.
Bord na Móna Recycling worker Mick Gleeson was part of the delegation that visited Leinster House this afternoon.
"We had townhall meetings with the company this week but no guarantees could be given to us about our terms and conditions after the sale, that's what's causing the most anger and frustration.
"It was the question that probably brought the most heat, ire and anger in the meetings.
"We don't know what the future holds."
SIPTU members are due to meet with the company again on Tuesday and will decide on their next steps following those talks.
"We'll have some questions that we need answers to, but if we don't get some sort of guarantees, then I would say nothing will be off the table up to and including strike action," Mr Gleeson said.
The company said that while the operation will no longer be part of the Bord na Móna group, employees will continue to work for the recycling business with no change to their contractual terms and conditions of employment on handover.
Bord na Móna Recycling provides waste collection services for homes and businesses across Leinster and north Munster.
"The transaction follows a strategic review conducted by Bord na Móna of its recycling business which concluded that a sale would enable the business to achieve the scale and efficiency required for sustained growth, profitability and employment," the company said in a statement.
"Bord na Móna Recycling will continue to provide services as usual for its household and business customers pending regulatory approval of the transaction," a spokesperson said.
The terms and value of the deal have not been disclosed.
