Australia's opposition party officially has launched its election campaign, putting health care and climate change at the forefront of its bid for election within two weeks.

Center-left Labor Party leader Bill Shorten on Sunday promised to spend billions of dollars providing free dental care for pensioners, reducing waiting times at hospital emergency departments and eliminating costs for cancer patients.

Shorten also highlighted Labor's pledge to reduce Australia's greenhouse gas emissions by 45% below 2005 levels by 2030. The conservative coalition government has committed to reduce emissions by 26% to 28% in the same time frame and warns that Labor's more ambitious target would wreck the economy.

Prime Minister Scott Morrison says his government will reduce taxes for all if reelected on May 18 for a third three-year term.