Six vehicles were set alight in Richardson in the early hours of Wednesday morning.
At 3:30am Wednesday, police found find five vehicles damaged by fire on Prichard Circuit.
They then found a sixth vehicle ablaze on May Gibbs Close.
Police said they were investigating the circumstances surrounding the fires.
Anyone with information or who may have witnessed suspicious activity in Richardson were urged to contacted police via Crime Stoppers on 1800 333 000 or via the ACT Crime Stoppers website.