Large damage bill from fire at NSW school

A NSW secondary school is facing a damage bill in the hundreds of thousands of dollars after a fire broke out in the early hours of Wednesday.

Albury High School, on the NSW southern border, faces the costly repair bill after IT equipment and computer servers were destroyed in the blaze in an administration building.

Firefighters were called to the school about 1.30am on Wednesday and extinguished the flames.

"The repair work and replacement of the damaged equipment in there would probably be several hundred thousand dollars," Fire & Rescue NSW Inspector Stewart Alexander told AAP.

The school was closed on Wednesday as it had no power or water.

Students were expected to return on Thursday.

Insp Alexander said the incident was due to an electrical fault and there were no suspicious circumstances.

"There were no signs of forced entry... I'm confident it wasn't a deliberately lit fire."