The pilot was flying a Cessna 185 aircraft on a VFR charter flight from Moorabbin to Peterborough with 2 passengers. On arrival at Peterborough he overflew the strip and estimated the wind to be from 220 degrees at 5 to 7 kts. The strip has an uphill gradient to the east, and, even though this would result in a slight tailwind from the right quarter for the landing, the pilot elected to accept this and make use of the uphill gradient. The landing was reported to have been smooth and light and was accomplished with a trickle of power and full flap (4 stages). During the roll out the aircraft diverged slightly left and then made a rapid and increasing swing to the right. Application of rudder and brake was not able to stop the developing ground loop. The aircraft left the mown strip with the group loop tightening until the left main landing gear collapsed. The aircraft came to rest pointing back down the strip towards the touchdown point. After shutting down the engine the pilot and passengers evacuated without assistance or injury. The pilot considered that he should have used a different technique when landing. A powered approach with 2 stages of flap, raising the flaps as soon as possible after landing, and using power to ensure adequate rudder authority during roll out would have result in control of the aircraft being maintained.