The man was walking along the park’s main path between 10.55pm and 11.05pm on Saturday (April 1) when he heard a noise behind him.
On turning around, he was pulled to the ground and assaulted by four men, who made off via the swing area.
All four offenders were white men in their 20s and wore hooded tops, one with his hood up covering his face and spoke with a local accent.
Officers would like to speak to anyone who may have witnessed this incident or who may have any information about it.
Witnesses or anyone with information can contact police on 101 or Crimestoppers anonymously on 0800 555111.