HONG KONG - Hong Kong school teachers bombarded by daily instant messages from parents and students after work - a practice also seen in Singapore - want schools to put an end to this form of informal communication, a survey has found.

A majority of 500 teachers from primary and secondary schools interviewed in January said the easy access to them after school - even after midnight - has upset their private lives and caused them sleepless nights, the South China Morning Post (SCMP) reported.

The Federation of Education Workers, which conducted the survey, said the teachers hoped that schools would provide a guideline allowing them to go offline after work.

"A teacher is in charge of over 100 pupils every year," federation vice-chairman Wong Wai Shing was quoted as saying by the SCMP.

"If all their pupils' parents sent messages to their teachers, they'd have to handle these messages 24 hours a day, which is absolutely unhealthy."

The survey shows 93 per cent of respondents continued to discuss work with their colleagues outside school hours via messaging tools, such as WhatsApp, WeChat and Facebook.

It also found 51 per cent handled parents' enquiries, 48 per cent answered pupils' questions relating to school work, and 27 per cent counselled their pupils using these platforms.

While 72 per cent of the teachers interviewed acknowledge that the interactions improved the flow of information, 67 per cent felt the messages had affected their private lives and 61 per cent said the after-work communications had intensified their job pressure, the SCMP reported.

One teacher, Mr Simon Wong Yun Keung, said he was added to an average of 12 WhatsApp groups each year.

"Every class has its own group, and every school department has its own group," he said.

"We hope the schools will not punish teachers for not handling after-work messages immediately."