Japan is considering raising so-called adjustment allowances for public school teachers, which are paid instead of overtime pay, for the first time in about 50 years, sources have said.

A special subgroup of the Central Council for Education, which advises the education minister, is examining boosting the adjustment allowances, currently set at 4% of monthly salary, as part of measures to improve the treatment of public school teachers, the sources said Friday.

There has been a proposal for raising the allowances to 10% of monthly salary or even higher, the sources added.

The allowances are based on the special measures law on salaries of educational personnel of public compulsory education schools, which entered into force in 1972.

Over how to improve working conditions for public school teachers, some experts have proposed that the current fixed-amount allowances be replaced by overtime benefits whose amounts vary depending on the hours of overtime worked.

But at the subgroup, an increasing number of members think that given the difficulty of clearly separating the hours worked from those that teachers spend on related activities, it would be better to improve the treatment of teachers without changing the adjustment allowances, the sources said.

In May last year, the ruling Liberal Democratic Party proposed raising the allowances at least to 10% of monthly salary.