School leaders say some rural families may be forced to home-school their children if hostel workers succeed in getting the minimum wage for the hours they sleep over at boarding school.
School hostel supervisors are following the lead of disability workers, seeking the minimum wage for the hours they sleep in school boarding facilities.
The Service and Food Workers Union says it has made a claim for about 20 hostel workers and wants it resolved urgently.
In September, nearly 4000 disability workers settled a deal that will phase in the minimum wage for the hours they sleep over.
Service and Food Workers Union national secretary John Ryall says the hostel workers already get an allowance for sleeping over but they should get the minimum wage.
"Most of them are getting about $30 a night and they should be getting about $120 so that's about a $90 difference, although that does vary from hostel to hostel," he says.
Mr Ryall says the claim covers both state and private schools and the increased cost would not be great.
The Secondary Principals Association and the owners of Integrated Schools say any pay rises would have to be passed on to parents, some of who may not be able to afford to send their children to school.
They warn that if the claim is successful, some school hostels will have to close.
They say they are taking legal advice and will meet next month to discuss the claim.