An aggressive species of marine bacteria responsible for many more deaths than sharks worldwide each year has been found in Sydney Harbour, with experts predicting outbreaks in spots along the city's waterfront as water temperatures rise with global warming.

Vibrio bacteria, which includes the species that causes cholera, can cause serious illness in humans and animals, including gastrointestinal sickness through consumption of contaminated seafood and flesh-eating infections in swimmers.

According to a new study by University of Technology Sydney scientists, two species of potentially dangerous Vibrio bacteria were detectable in particularly high concentrations when the water was warmest and in areas of mid-salinity, around Parramatta Park, Olympic Park and Rozelle.

In the report, published in Frontiers of Microbiology on Tuesday, UTS researchers detail the composition of water samples collected from Sydney Harbour between Parramatta Park and Chowder Bay.