Labor leader Bill Shorten has challenged the government to ‘bring on’ a climate change election at the party’s national conference in Melbourne.

The opposition leader focused heavily on climate policy and renewable energy during his speech to delegates on Friday, which included a pledge for an emissions trading scheme (ETS).

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While the announcements drew applause from party faithful, there was audible booing when Mr Shorten touched on immigration policy, which now includes a commitment to tow back asylum seeker vessels.

The wide-ranging address also pledged:

• half of Labor’s MPs to be women by 2025

• a promise to build Australia’s fleet of submarines locally

• support for same sex-marriage

But the Labor leader fixed much of his attention on climate policy.

Mr Shorten vowed to enact a 50 per cent renewable energy target by 2030 and implement an ETS.

“We will not be intimidated by ridiculous, fear-mongering scare campaigns that will come. Let me say this to our opponents, in words of one syllable – an ETS is not a tax.”

“And if Mr Abbott wants to make the next election a contest about who has the best policy solution for climate change, I’ve got a three-word slogan for him: Bring. It. On.”

He said Australia was behind other western nations in renewable energy investment.

“Last year, around the world, investment in renewables rose by 16 per cent. In China alone, up by 33 per cent. In Australia, down by 88 per cent,” he said.

He also reiterated his support for an Australian republic.

“Let us make this the first decade where our head of state, is one of us. We can be an Australian republic, with an Australian head of state,” he said.