A young child was assaulted in a play area at the Hellenic Club, police say.

Police revealed the alleged assault, which reportedly happened mid last week, on Monday afternoon. 

Police could not confirm if a parent, a child or another person was involved in the assault, which took place between 7.30pm and 8.15pm on Wednesday, December 18. They were unable to give an age for the child, or provide any information about the circumstances of the alleged assault.

ACT Policing said they received the report of the assault on December 20.

"Police would particularly like to speak to a witness described as male, aged between 10 and 18-years-old with short dark hair," a spokeswoman said.

"He was wearing a blue T-shirt with writing on the front and dark shorts or pants and white shoes."

Anyone who was in or near the children’s play area and can assist police with their investigation should contact Crime Stoppers on 1800 333 000 or at www.act.crimestoppers.com.au.