CANBERRA, Australia >> Opposition leader Bill Shorten used his center-left Labor Party’s official campaign launch on Sunday to cast July 2 general elections as a referendum on the future of Australia’s universal health care system.

A Labor government introduced government-funded Medicare in 1983 to provide free or subsidized health care for all Australian citizens and permanent residents. Labor argues the conservative coalition government plans to privatize Medicare — a claim Prime Minister Malcolm Turnbull denies.

“If you want to know why this election will make a difference to you, your family, your street, your workplace, to Australia’s future, I can give you the answer of why politics matters in one word: Medicare,” Shorten told a Sydney auditorium in front of the slogan: “We’ll put people first.”

The government has been quick to assure the public that the popular heath care system is not under threat.

Turnbull, who will officially launch his conservative Liberal Party’s campaign next weekend, announced on Saturday that his government had scrapped plans to outsource the Medicare payments system to private enterprise.

“Medicare will never ever be privatized,” Turnbull told reporters Sunday. “What Bill Shorten is doing is peddling an extraordinary lie so audacious … it defies belief.”

Six weeks after the election was called, Shorten launched his campaign in western Sydney where Labor hopes to win several seats from the government.

An opinion poll published by Fairfax Media on Saturday showed Labor ahead of the government with support of 51 percent of respondents compared to 49 percent for the conservative coalition. But this lead is within the poll’s 2.6 percentage point margin of error.

The poll was based on a nationwide telephone survey of 1,437 voters from June 14 to 16.

Many analysts don’t believe Labor’s support will deliver the 21 seats it needs to form a majority in the 150-seat House of Representatives, where parties form governments.

All but one of Labor’s surviving prime ministers attended the launch: Bob Hawke, Paul Keating and Julia Gillard.

Kevin Rudd, who was ousted by Gillard in an internal party showdown in 2010, then replaced her in a similar coup in 2013, was in Russia on business.

Since Rudd was elected in 2007, there have been four changes of prime minister in an era of extraordinary volatility in Australian politics.

Shorten was a powerbroker within the party who was instrumental in overthrowing both Rudd and Gillard.