The Victorian government will pledge to cut the state's greenhouse gas emissions by up to a fifth by 2020, putting it at odds with Canberra as the state positions itself as the national leader on tackling climate change.

The target – a reduction of 15 to 20 per cent – will be achievable only because of the closure of the Hazelwood coal power station in March, announced by its French-majority owners last year. But it will also require other cuts through energy efficiency and renewable energy programs.

It deepens the divide on climate between the state Labor and the Turnbull Coalition government, which will meet a less exacting 2020 target and has been sharply critical of the cost of Victoria's ambitious renewable energy policy.

Victorian Energy, Environment and Climate Change Minister Lily D'Ambrosio said 2016 was the hottest year on record, and the state wanted to maximise job and investment opportunities through a forward-thinking approach to tackling the problem.