Police have confirmed they are investigating 10 reports of needles being found in punnets of strawberries including one involving a Perth primary school student who reported a case on Tuesday afternoon.

Police said the boy was at his primary school in Willetton when he took a bite out of a strawberry and found a needle. It is understood the boy reported the needle to his teachers.

The latest case is one in five WA reports police are investigating of needles found in strawberries, including in punnets bought from York, Kelmscott, Spearwood and Bull Creek.