Gas great for Australia, says PM Turnbull

Prime Minister Malcolm Turnbull has talked up the prospects of gas boosting Australia's wealth and providing clean energy while hundreds of protesters criticised it as dangerous for the environment.

Australia is already the world's largest seller of iron ore and would be the largest liquefied natural gas exporter in less than four years, Mr Turnbull said.

Gas was an important transition fuel on the way to renewables, the prime minister told VIPs including West Australia Premier Colin Barnett at an LNG industry event in Perth.

He praised LNG projects such as Gorgon off WA's coast, which he visited on Monday and is the largest resource project ever built in Australia, as having a tiny effect on the environment while producing massive amounts of energy.

"Gas produces 50 per cent less emission than a coal-fired power station," he said.

Hundreds of protesters at Perth's King's Park could be heard during Mr Turnbull's speech, shouting against gas and fracking or underground drilling because of its environmental impacts.

Despite gas being cleaner than coal critics say it is still a dirty energy source that emits carbon dioxide and that the climate cannot afford.