The senior firefighter who attended two fires at Wellington's Basin Reserve says he's not sure if the blazes were the work of a copycat, but they are suspicious.
Emergency services called at 9.45pm on Thursday found one blaze at the back of the entrance to the R A Vance stand and another near the toilet block east of the stand.
Central Fire Station senior officer Paul Lyall says the fires could not have started naturally, and the matter has been referred to the police.
Mr Lyall says the two buildings sustained only minor damage.
Wellington City councillor John Morrison, who is also a Basin Reserve trustee, says the time has come to look at changing the venue's 24-hour access policy.
Mr Morrison says there has been vandalism and tagging at the Basin Reserve recently and he would like to see the gates shut from 7pm to 6am.