The GWU's Police Officers' Union has ordered its members not to wear their uniform hat and not shave, in protest over a stalemate in talks on duties near schools.
The union is insisting that the closure of roads while children are going to or leaving school can be handled by others.
The current situation it said, is seeing police stations deprived of some 70 officers every day. It argues this is not part of police work as laid down by law.
Talks held over the past weeks with the Home Affairs Ministry had not led anywhere, the union said.
The directive comes into force on Saturday morning.