A professor of planetary science says humans could be living on Mars within 25 years.

Professor Jeff Taylor from Hawaii's Institute of Geophysics and Planetology is addressing a conference in Perth today.

He says humans could be living on the moon within 15 years, and if basic life supports like oxygen and water can be secured, humans could colonise Mars within 25 years.

Professor Taylor says it is human nature to want to explore and colonise new areas and humans may go to Mars for economic reasons, or to secure additional energy supplies.

He says once people start living on the moon, new businesses will be established.

"Whether that's going to be servicing and building telescopes or servicing satellites in orbit around the Earth, including communication satellites deep in synchronous orbits, or any other commercial ventures including space tourism," he said.

Professor Taylor says the first step would be to secure basic life supports on the planet.

"There is plenty of water which you not only use for drinking, but you can split it into oxygen and hydrogen and use it for life support," he said.

"You can also make fuel from it. Mars is really quite rich in those sorts of resources."