A devastated mother claims her five-year-old son was sexually assaulted by another child at an Adelaide kindergarten.

It’s understood police investigated the allegations but no charges were laid because the accused boy is too young.

The boy told his mother (neither can be named) he was being bitten and hit by the other child but then the abuse escalated.

He revealed he’d been lured behind a shed where the other boy allegedly performed a sex act on him.

View photos The boy alleges he was sexually assaulted by another child at kindergarten. Source: 7 News More

“He told me that the boy had made him pull down his pants because he wanted to play a game,” the boy’s mum said.

“I was in complete shock and disbelief thinking, ‘Is this really true?’”

The mother withdrew her son from the kindergarten and reported it to staff.

She said staff told her son “you need to make better friendships”, but claims the alleged abuser struck again with attacks on two more boys on Friday.

The kindergarten sent a letter home to parents asking them if their children had expressed concerns about inappropriate behaviour.

View photos The mother was shocked by what her son told her. Source: 7 News More

The accused has since moved kindergartens but the mother of the alleged victim wants assurances it won’t happen to another child.

She said she’s been told the boy will have a one-on-one carer wherever he goes.

The education department says staff have been given a refresher course in how to recognise sexual behaviour in pre-schoolers but the alleged victim’s mother said it’s too late for her son.

“You know he’s got a sister,” she told 7 News.

“I have to watch now just to be careful and aware of because of what he’s been introduced to.”