Workers on building sites are planning a one-day stoppage in January over safety conditions.
It follows a number of fatalities on construction sites in the last few weeks.
Earlier today building workers brought traffic to a standstill in Dublin when they held a demonstration over workplace safety.
SIPTU's Eric Fleming says higher penalties for dangerous work practices must be brought in and enforced.
"Judging by the response and the anger by members there is no doubt about it," he said.
"I think it will go ahead because we have to get that message across loud and clear that unless builders sit up, and take notice and unless the penalties are dished out to them, we are not taking anymore of this.
"As far as we are concerned we will stop wherever jobs are dangerous and we will instruct our members to stop."