Bricks were thrown at firefighters when they went to a park after wheelie bins had been set alight.
Youths dragged the bins onto Ashfield Park in Standish and deliberately set them on fire last night.
Crews from Wigan fire station were called at around 9pm to put out the fires.
But when they arrived, bricks and stones were thrown at them.
Crew manager Jon Roscoe said: "They attacked the crews there with bricks.
"Some of the youths were caught on CCTV and they will be investigated and prosecuted."
As well as attacking the firefighters, the group of youths got larger and they continued to light fires.
Mr Roscoe said: "Initially I think there were four or five youths, then as we were trying to put the fire out, they were dragging more bins and it grew to about 20 or 30."
Another fire engine attended and police were also called to deal with the incident.
Fortunately no-one was hurt, but there was damage to the children's play area in the park.
Mr Roscoe warned that firefighters being at the park affected emergency cover across Wigan.
Police confirmed they were called to the park at 9.10pm and were investigating what had happened.
Anyone with information is asked to contact them on 101, quoting log 2044 of September 3.