Police are investigating four teenage boys who allegedly defied a total fire ban by sparking a grass fire in Wollongong on Friday.
Police said the four 14-year-old boys started the fire at Albion Park on Friday by lighting an incendiary device at Chapman Place about 9pm.
A total fire ban for the area was in place at the time.
The boys tried unsuccessfully to put out the fire, police said in a statement.
The father of one of the boys also tried to extinguish the blaze, but he too failed, sustaining burns to his feet.
Fire and Rescue NSW subsequently put out the blaze.
Police are investigating the incident.