Emergency services were called to a fire at Paratutu rock, in New Plymouth last night around 9:30pm.
Police received reports from witnesses saying there was a group of people letting off fireworks on the seaside face of Paratutu rock around the time of the fire.
Detective Simes of New Plymouth CIB wants anyone from that group or anyone with information that could help identify members of the group to front up.
With temperatures still high and vegetation dry, police advise taking extra care when using anything that may be an ignition source in outside areas.
Detective Simes can be reached on (06) 215 4178 or anonymously through Crimestoppers on 0800 555 111.