The new taskforce have started investigations over the two suspicious blazes.
The state's new bushfire taskforce are already at work, after two fires earlier this week have been deemed suspicious.
Strike Force Vulcan officers are seeking witnesses over the two separate incidents in Rockingham and Waikiki on December 6.
The first fire was reported around 4:35 on Wednesday afternoon in a park surrounded by Santa Monica Drive, Bolsabay Drive, Ennis Avenue and Buttermere Approach in Waikiki.
Meanwhile a second fire was reported around 6:15 that evening, in bushland near the corner of Simpson Avenue and Louise Street in Rockingham.
Emergency services were called to, and extinguished both blazes.
Around 20 metres of bushland was burnt.
Both fires are being treated as suspicious and anyone with information or who witnessed the start of the fires is being asked to call Crime Stoppers on 1800 333 000.
There are rewards of up to $50,000 for information that leads to the identification and conviction of an arsonist.
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