Police said a man, 23, was arrested about 2.15pm on Tuesday.

"He was taken to Orange police station and charged with destroy property in company causing fire valued at more than $5000," a statement said.

The man was refused bail and was due to appear in Orange Local Court on Wednesday.

Detective Chief Inspector Bruce Grassick said police anticipated further charges would be laid.

"There is presently another person assisting us with our inquires," he said.

"We believe there is only two persons involved with this matter."

Detective Chief Inspector Grassick, the Central West Police District crime manager, said police investigations and witness accounts led to "some significant breakthroughs" earlier in the week.

"We understand, and the allegations are there was a number of persons at that location all known to each other," he said.

"The 23-year-old male, we will allege, has taken a bin lid and has lit that bin lid which has subsequently taken hold and has caused the fire in the grandstand."

Detective Chief Inspector Grassick said the fire had damaged about 40 per cent of the grandstand.

"A large amount of junior football gear has been damaged and is unusable, so that is a significant impact on that rugby club and trying to move forward into the next season and having those young children playing the game they love."

The fire was reported to authorities at about 2.15pm on Saturday.

Fire crews took about 30 minutes to bring the fire under control.

The Orange City Rugby senior and junior clubs have lost sporting equipment including posts, padding, kit bags and sporting clothing in the fire.