The body was found after it was run over by a tractor-drawn grass mower, which was being used near to the Steinspornbrücke bridge on Wednesday morning at 9am.
Police are now investigating whether she was dead before being run over. "Circumstances suggest that she was already dead," police spokesman Patrick Maierhofer said. An autopsy has been ordered.
Maierhofer said that the woman was fully dressed and had an ID card with her. The grass she was lying in was around one metre high - and is part of a large green space which connects the Lobau nature reserve with the Donauinsel and is used by cyclists and walkers.