Australia's Loretta Harrop has won the Olympic triathlon silver medal, finishing behind Geelong-born Austrian Kate Allen who sprinted past the Queenslander on the finish line.

Harrop, 29, had led throughout the 1.5km swim, 40km cycle and 10km run until just before the end when the fast-finishing Allen swept past her, leaving Susan Williams of the US to take the bronze.

Allen, 24, had been 44th after the swim and the 12th after the cycle leg and appeared out of the medals until she ran down the leaders with a withering final burst.

Harrop and American Sheila Taormina had led out of the water, with fellow Australian Rina Hill and America's world No.1 Barb Lindquist completing a quality lead bunch of four heading onto the bikes.

Maxine Seear, the teenager in the Australian team, was 16th after the swim, just over a minute behind Harrop but both she and Hill faded in the searing Athens heat to finish down the field.

Harrop, though, relished the tough going and shook off Taormina late in the cycle leg to establish a 17-second buffer over the world champion, with another American Barb Lindquist and Williams another one second behind.

Harrop increased her advantage to 29 seconds over her nearest rivals after the first of three run laps along the scenic coastal course.

But Harrop, who was fifth at Sydney 2000 and seemingly had the race wrapped up, could not respond when Allen bolted past her with just a few metres to go.

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