Fire destroys admin building at Morphett Vale church

Investigators believe a fire that gutted an administration building at the Harvest Australia Church (HAC) in Adelaide's southern suburbs was deliberately lit.

The blaze broke out just before 6:30am (ACDT) in a transportable on the site of the HAC and Southern Vale Christian College at Morphett Vale.

Seven firefighters from the Country Fire Service (CFS) took around half an hour to extinguish the fire, which left a $100,000 damage bill.

Kevin Churchward from the CFS said there was a lot of flammable material inside the transportable.

"The building does seem to be admin-related so there's probably a lot of combustibles - paper, cardboards and so forth," he said.

"The inside is quite gutted."

Police said the building was unoccupied at the time.

Party-goers escape burning house

Meanwhile, about 30 party-goers had to flee a two-storey house at Wynn Vale in the north-eastern suburbs when a fire broke out after midnight.

Metropolitan Fire Service responded to the call at Sunrise Court at about 1:40am.

Sixteen firefighters extinguished the blaze, which was believed to have started in the roof space before spreading though a ducted air conditioning vent.

No one was injured in the blaze and the damage bill was estimated at about $180,000.