Hundreds of students arriving for their first day of the year at NSW public schools last week found out there were no classrooms for them, as the Department of Education scrambles to get 46 demountables into overcrowded schools.

At Bondi Beach Public School, two classes are being held in the school's library and learning centre after students returned on January 30 to find the demountable classrooms needed to house its growing population would not arrive for at least several more weeks.

A year 1 class and a year 5 class at Bondi Beach Public School are currently being held in the library and learning centre as students wait for much-needed demountable classrooms to arrive. Credit:Janie Barrett

Six classes at Carlingford West Public School are being held in the school hall and library or students are sharing classrooms, as the school waits for demountables that were only delivered on the first day of school to be fully installed.

"We're still waiting for the stairs to be put in so the demountables can't be used yet," Carlingford West Public's P&C vice-president Bettina Corbo said.