Siptu is demanding an urgent meeting with Ladbrokes Bookmakers
The bookies, which employs more than 800 people in its chain of almost 200 shops in Ireland, has warned that redundancies are likely as it restructures.
All of the shops will continue to trade as normal during the examinership process.
Siptu, which represents around 280 Ladbrokes' staff, says it believes the future of up to 60 of the shops is under consideration and it wants to discuss the potential impact on its members.
Workers at betting offices around Ireland were briefed on the news.
Jackie Murphy, retail director of the Irish operation, said: “We are taking this action to safeguard our business and position it for future growth. The examinership relates solely to our retail operations and has no impact on Ladbrokes telephone and digital services.
“We are fully committed to work with all our staff through this difficult time and would hope that the vast majority of any necessary redundancies will be voluntary.
“It will be business as usual with shops taking and paying bets as normal while this process is ongoing.”