The Country Fire Authority was called out to a small fire at the Morwell Skate Park on Saturday night.
Morwell police said they were investigating the deliberately lit fire ignited in the mulched garden area alongside the skate park about 6.50pm.
Police said there was no property damage other than to the garden area.
Anyone with information should phone Criminal Investigation Unit on 5131 5000, Crime Stoppers on 1800 333 000 or visit www.crimestoppers.com.au