Neighbours helped extinguish a fire at a south Canberra motor home park that has left one caravan with extensive damage.

The fire at the Symonston caravan park on Canberra Avenue started shortly before 3.40pm, and was caused by an electrical fault in a caravan.

The residents, who were home at the time, escaped the caravan, and were joined by neighbours who helped fight the blaze before fire crews arrived.

The fire, now extinguished, left the caravan with significant damage, and the surrounding annex with smoke damage.

There were no serious injuries.