Australians will go to the polls in a general election on May 18 after Prime Minister Scott Morrison fired the starting gun Thursday on a campaign set to be fought over taxation, climate change and inequality.

Morrison and his main opponent, Labor Party leader Bill Shorten, both used the Australian phrase "a fair go" to frame their campaigns around a national sense of equality and opportunity, albeit from very different angles.

Opinion polls have had center-left Labor well ahead for years and show that the coalition of Morrison's Liberals and the rural-focused National Party is headed for a resounding defeat.