Australia's opposition Labor party officially launched its election campaign yesterday with a plan to create 30,000 jobs a year.

Hoping to gain much-needed momentum in the final two weeks of the campaign, party leader Bill Shorten gave a rousing address at the Labor party's official launch in western Sydney, declaring that "a great future is within Australia's reach".

Despite opinion polls indicating that Prime Minister Malcolm Turnbull is on track to win the election on July 2, Mr Shorten insisted Labor can still achieve victory and urged supporters to "dig a little deeper, work a little harder, be part of something bigger".

"Mr Turnbull says he's got this in the bag, he claims he's already won it," Mr Shorten said. "I say to him: never underestimate Labor - you ain't seen anything yet."

Mr Shorten used the speech to warn that the ruling Liberal-National Coalition had a "secret plan" to privatise the national health scheme, Medicare.

"Piece by piece, brick by brick, the Liberals want to tear Medicare down," he said.

Mr Turnbull has insisted he will not privatise Medicare and accused Mr Shorten of "extraordinary and audacious" lies.

"Any improvements to the way Medicare interacts with Australians will be done within and by government," Mr Turnbull told reporters yesterday.

The launch was held in the marginal seat of Lindsay, one of several Liberal-held western Sydney electorates which Labor needs to win to defeat Mr Turnbull. Opinion polls indicate that the Coalition is slightly behind Labor across the country, but has a strong lead in most marginal seats.

Mr Shorten ended his speech alongside his wife Chloe and was greeted by their young daughter Clementine, who leapt into his arms. The launch was attended by former Labor prime ministers Bob Hawke, Paul Keating and Julia Gillard but not by Kevin Rudd, who was in Russia for a conference.

"We gather as one united party: ready to serve, ready to lead, ready for government," Mr Shorten said.

Australian political parties tend to launch their official campaigns close to the election because MPs can typically no longer claim parliamentary travel allowances after the launch.

In addition, the launches are intended to appeal to the large numbers of voters who make their minds up in the final days before the election.

Mr Turnbull is due to launch his campaign on June 26, just six days before the election.

In an attempt to combat Mr Turnbull's campaign mantra of "jobs and growth", Mr Shorten yesterday released a A$257 million (S$256.5 million) jobs creation plan.

If elected, Labor will give an A$20,000 tax concession to small businesses which employ mothers returning to work, older job seekers or young workers under the age of 25.

"Supporting these Australians into work will create around 30,000 new jobs every year," Mr Shorten said.

"This is a real jobs plan - and a responsible tax cut. It's a plan to grow small businesses - and to help people back into the workforce."

Mr Shorten also outlined Labor's wide range of plans to reduce carbon emissions, combat domestic violence and suicide, legalise same-sex marriage, boost school funding and create a royal commission into the banking sector.

Analysts praised Mr Shorten's performance but noted that the launch may not deliver the momentum required to give him any chance of winning.

Political commentator Mark Kenny said Labor's admission during the campaign that it would increase the budget deficit had made voters worried.

"Shorten, a leader who has grown with the campaign, rose to the occasion," wrote Mr Kenny on Fairfax Media websites.

"But if the goal was to quell fears of too much spending… it probably fell short."