A Tasmanian scientist says the discovery of water on Mars could indicate that the planet has microbes similar to those found in Antarctica.

Scientists analysing NASA data say they have found evidence of flowing salty water on the surface of Mars.

University of Tasmania Professor John Bowman said any proposed life on the red planet would most likely take the form of small microbes beneath the surface.

Professor Bowman said the discovery of larger organisms is unlikely unless Mars experiences human interference.

"You're talking about a project which would take a long time, maybe centuries," he said.

"We would have to add microbes to the environment that could some how generate more gas into the atmosphere, for instance more CO2 or nitrogen and also more oxygen as well.

"It will probably not change unless we humans go to Mars and actually do something radical there.

"Like a process in science fiction which is called terraformation, which is a possibility."

Professor Bowman said any organisms on the planet would most likely represent those found in cold environments.

"There are some microbes that live in very, very salty environments," he said.

"So there's a possibility some of these could be similar or related perhaps. It's likely that microbes living on Mars would be underground, not living on the surface.

"It would be too extreme, even for any microbes that we know on earth."