The federal Opposition has promised for the first time a Shorten Labor government would hit the well-off with a 2 per cent tax hike within 100 days of taking office, and reverse the cuts to penalty rates for 700,000 Australians that begin this weekend.

Both of these moves – along with his plan to legalise same-sex marriage within 100 days – are designed to be a direct pitch to mainstream Australia, and to show Labor is ready to govern.

In an exclusive interview with Fairfax Media on the one-year anniversary of Mr Turnbull's narrow election victory, Mr Shorten promised a return to consensus-building politics and suggested his time as leader of the Australian Workers Union will help him govern for the majority of Australians.

"I don't know who I will face at next election but whoever it is, we will have a program that speaks to the lives of Australians ... who the Liberal Party pick [as leader] is up to them, I'm trying not be drawn into, too much, what they are doing," he said.

"My opposite number is an out-of-touch elitist, so is his party. It has been a year of disappointment and debacle...how on earth is it that on the first anniversary of his [Mr Turnbull's] second term, we get a tax cut for millionaires and a kick in the bum for 700,000 people, who get a penalty rate cut?

"Some of our program, which we can announce today, is that we will reverse tax cuts for millionaires and we will legislate to reverse penalty rate cuts in the the first 100 days."

As middle-class Australians brace themselves for big hikes in their gas and electricity bills from July 1 that will run into the hundreds of dollars, Mr Shorten made a direct pitch to people concerned about the sky-rocketing cost of living.

"Electricity and gas prices are out of control. The government can't blame the carbon tax, it was [elected] four years ago ... if you are a middle-class Australian, you don't have a sense of confidence in the economy because wages are flat, and electricity prices are going up, the cost of university is going up ... these are big problems," he said.

"We will be in a position by the next election to present a social and economic program for the betterment of the nation and its people, its citizens. We recognise that what Australians want is a government on their side."

Mr Shorten has not previously said the changes to penalty rates, or the 2 per cent rise in the top marginal tax rate, affecting anyone earning more than $180,000 per year, will happen so quickly.

The promises come after a week in which the Coalition government again erupted into factional infighting over same-sex marriage, defence policy and provocative bomb-throwing speeches from former leader Tony Abbott.

Mr Shorten said what mattered to Australians was whether or not they could get hospital care, a job, buy a house and get a good education for their kids – not Coalition infighting.

The Coalition has now trailed Labor for 14 consecutive Newspolls. Mr Shorten would be the first former union leader since Bob Hawke to be elected prime minister.

While the Coalition has attempted to use Mr Shorten's time as AWU chief against him – and the trade union royal commission raised questions about some of the deals struck during his time as leader – the Opposition Leader said the lessons he learned in the union movement would make him a more effective prime minister.

"I'm a consensus builder, I do that in the workplace, I helped do that with the NDIS," Mr Shorten said.

"I always understood in the workplace that change was inevitable. But it has to benefit people. When it works well, people have a say."

While the election can be held as late as the second half of March 2019, many MPs in both major parties expect Mr Turnbull to call the poll in August or September 2018, to avoid clashes with the Victorian and NSW state elections, due in November 2018 and March 2019 respectively.

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