The Service and Foodworkers Union says its members at Christchurch Casino are increasingly worried about their future and fear they will lose their jobs.
Some 538 people are employed at the casino, which has remained shut since the earthquake on 22 February.
They are being paid until 5 April, at a cost of about $400,000 per week.
But the union says they have heard nothing definite about their continued employment and want to know what will happen.
Casino management says a civil engineers' report on the state of the building is expected in the next couple of days.