As many as 2,000 teachers are at risk of losing their jobs when the new school term begins in September.
That's due to falling demand for places in secondary schools, according to a survey of government-run and subsidised schools by the Professional Teachers' Union.
The 47 schools that participated in the survey for more than 400 institutions said they would cull about 5.5 teaching positions on average from September.
The news comes a day after parents in the northern New Territories complained that they had failed to secure places for their children in primary schools because of competition from mainlanders.
On its part, the union has released an open letter to chief executive-elect Leung Chun-ying, urging him to halt the current administration's policy of closing schools that fail to meet a minimum enrolment number.
According to Education Bureau regulations, secondary schools must enrol 61 pupils a year to avert closure.