Firefighters attended a 'suspicious' blaze at Mereside Park after they were alerted by a 999 call, say fire services.
Crews from South Shore went to the scene of a van fire on Clifton Road at around 4.30am on 1 March.
A spokesman for South Shore fire services said: "A fire engine and crew from South Shore responded to the 999 call alerting them to a van on fire in the park.
"Firefighters used a hosereel jet to extinguish the fire and called the police to report what was believed to have been arson."
Nobody was injured during the incident.
A joint investigation between the police and the fire service has been launched.