Two pieces of play equipment at Amington Recreation Ground were set on fire some time overnight on Tuesday August 11.
The climbing wall has been completely destroyed and a small slide and platform have been badly damaged.
The equipment has been cordoned off pending an assessment. Once the safety report has been completed, decisions on repair and replacement will be made.
Only the affected parts of the play area have been cordoned off – the rest is still open for use.
Cllr Stephen Doyle, Cabinet member for Communities & Public Health, said: “This mindless act of arson has spoiled a popular play area which is very well used by young children.”