Teachers will have to prove they are too sick to work under plans being drawn up by Sefton Council in a bid to crack down on staff absences.
The proposals could see school officials paying monitoring visits to the homes or hospitals of teachers who are incapable of leaving their beds.
The guidance states that "absence will not be accepted without close scrutiny", a policy that the council insists is in line with employment law.
Council chiefs have proposed this course because their schools are increasingly unable to bear the financial burden of teachers' "persistent failure to attend for work".
Under the new policy, teachers who take four or more sick days would be asked to explain their absences, and prolonged absences would be monitored by phone calls and face-to-face meetings.
The guidance states that teachers would need to give a specific reason for each illness. Simply stating they "are 'feeling unwell' is not acceptable".
The move has been met with outrage from teachers' unions, which have labelled the policy "harassment".
John Rimmer, the NASUWT's executive member for Merseyside, said: "We are opposed to this harassment, and the plan to use telephone contact in this way is an invasion of privacy." rv.