More than 500 people were evacuated from Adelaide’s SkyCity casino after a small fire ignited in a wall space last night.

A transformer, situated between the central marble hall and a toilet, overheated and sparked the fire just before 7pm.

A smoke detector activated a sprinkler in the toilet and alerted the Metropolitan Fire Service to the blaze.

Within minutes SkyCity staff evacuated the building and MFS firefighters located the fire and doused the flames after breaking into the wall cavity.

MFS crews locked down the casino for about an hour – searching the building to ensure no other fires had started elsewhere – before they allowed patrons back in.

Early estimates by investigators put the damage bill at less than AUD 5000. Water from the bathroom sprinklers drained without causing any damage.

A spokesman for the MFS praised the SkyCity management for the quick response and evacuation of the building.