Last week, a small bag containing white powder was discovered on school grounds at Mansfield Primary School.
School principal Nicole Comerford confirmed two students reported the find to the school, with the school immediately notifying the police, who attended and removed the bag.
Police advised the school that the bag did contain an illegal substance and subsequently undertook a search of the surrounding area.
"We have also undertaken a further full search of the school grounds," Ms Comerford said.
"At this stage, there is no reason to believe this substance belonged to anyone in our school community and the police have assured us there is no ongoing threat."
Police have requested anyone with information to contact Crime Stoppers on 1800 333 000.
