A NSW primary school has banned girls from wearing shorts and made the wearing of dresses mandatory against the wishes of a number of students and their parents.

Bathurst Public School recently edited its uniform policy, deleting the summer shorts option for girls and leaving only the tunic.

Short-changed: From left, Bella Morris, 6, and mum Zoe, Elliott Miller, 6 and mum Renee.

Parents say they only found out about the change when their girls came home bearing the news.

Zoe Rodwell assumed her daughter Bella, who is in kindergarten, had misinterpreted the message. ''It seemed absurd. I really didn't give it much thought,'' she said.