SIPTU officials are due to meet Minister for Social Affairs Seamus Brennan today to discuss the situation surrounding pensions in the construction sector.
The union has claimed that many employers in the sector are failing to make contributions to a mandatory pensions scheme for construction workers.
SIPTU wants the Government to introduce a centralised collection system to ensure that employers hand over the millions of euros the union says they are currently withholding.
Speaking ahead of today's meeting, spokesman Eric Fleming said if the Government was serious about boosting pensions coverage, it would take action immediately.
"Here's a scheme where it's legally binding for people in the industry to be in it and yet there's only 40% to 50% of people in the industry in it," he said.
"It's up to you [Mr Brennan] to come in with a hands-on approach and help us, through your department, to make the deductions. We can't trust the builders to do it any longer."