Australians go to the polls May 18

Australians go to the polls in a general election on May 18, Prime Minister Scott Morrison said on Thursday, in a campaign expected to be fought over taxation, climate change and inequality.

Scott Morrison's governing conservative coalition trails the opposition Labor Party

Prime Minister Scott Morrison says Australians will go to the polls in a general election May 18. (Rad McGuirk/Associated Press)

Australians will go to the polls in a general election May 18, Prime Minister Scott Morrison said on Thursday in Canberra, kicking off a campaign expected to be fought over taxation, climate change and inequality.

"Earlier this morning, I visited the governor general ... and he accepted my advice for an election to be held on 18 May," Morrison told reporters.

Morrison's conservative coalition is seeking a third three-year term. But Morrison is the third prime minister to lead a divided government in that time and only took the helm in late August.

Opinion polls suggest his reign will become one of the shortest in the 118-year history of Australian prime ministers. The polls suggest center-left opposition leader Bill Shorten will become the eighth prime minister since the country plunged into an extraordinary period of political instability in 2007.

Labor Leader Bill Shorten's party is leading in opinion polls. (Rob Griffith/Associated Press)

The election pits Shorten, a former labour union leader who for six years has presented himself as the alternative prime minister, and Morrison, who the Australian public is still getting to know.

Morrison is seen as the architect of Australia's tough refugee policy that has all but stopped the people-smuggling traffic of boats from Southeast Asian ports since 2014. The policy has been condemned by human rights groups as an abrogation of Australia's responsibilities as a signatory to the United Nations Refugee Convention.

The conservative coalition government has also maintained a policy adopted in the final months of a Labor government in 2013 of sending boat arrivals to camps on the Pacific island nations of Papua New Guinea and Nauru. Those who attempt to reach Australia by boat are told they will never be allowed to settle there.

Morrison remains proud of virtually stopping people-smuggler boat traffic. He has a trophy shaped like a people-smuggler's boat in his office inscribed with "I Stopped These."

Labor has promised to maintain the policy of banishing boat arrivals to the islands. But Labor says it would give priority to finding permanent homes for the asylum seekers who have languished in island camps for years.

Climate change policy is also a political minefield in a country that is the world's largest exporter of coal and liquefied natural gas and that has been one of the world's worst greenhouse gas emitters on a per capita basis because of its heavy reliance on coal-fired power generation.

Morrison's government aimed to reduce Australian greenhouse gas emissions by 26 to 28 per cent below 2005 levels by 2030.

Labor has promised a more ambitious target of a 45 per cent reduction in the same time frame.

With files from Reuters