Fantasy Park, as well as a Charthouse Primary School cubby house, were set alight about midnight on Tuesday, April 9.
Arson Squad detectives believe both blazes are suspicious.
City of Rockingham deputy mayor Deb Hamblin said the Rand Avenue playground’s main piece of equipment sustained the worst damage and was now beyond repair.
A City playground inspector attended and cordoned off the now unsafe area.
Cr Hamblin said the playground was a unique facility with special features and interactive play sculptures for hearing and vision impaired children.
‘The play equipment will cost between $20,000 and $25,000 to replace but the rubber softfall underneath, which was badly damaged, could cost up to an additional $10,000 to replace,’ she said.
‘This is a deliberate and thoughtless act of needless vandalism and I am shocked that anyone would intentionally damage a children’s playground, particularly such a popular high-use one.
‘The City will submit an insurance claim for the damage, but it could take up to a couple of months to have a new piece of equipment manufactured and installed.’
She said during this time, the swing set and the smaller playground would still be able to be used.
Cr Hamblin urged anyone with information that could assist police to contact Crime Stoppers on 1800 333 000.