Arsonists have caused £35,000 worth of damage to play equipment at Ystrad Mynach Park.
Emergency services were called at around 9.45pm last night, Thursday, June 29, and police have launched an investigation.
The fire is being treated as deliberate and has caused extensive damage to a climbing frame and other play facilities in the park.
The damage has been valued at approximately £35,000 and police are actively seeking who is responsible.
A spokesman for CCBC said: “This mindless act of vandalism has destroyed a much-loved play facility in one of our most popular playgrounds.
“We would appeal to residents to be vigilant and keep a close eye on all our community facilities and report any suspicious behaviour to the police.”
Anyone with information can call 101 or the independent charity Crimestoppers anonymously on 0800 555 111 quoting log number 557 20/06/17.