Labor emissions target 'mad' policy: Pyne

Labor's new climate change target is "a mad policy" that would lead to the reintroduction of a carbon tax, cabinet minister Christopher Pyne say.

Opposition Leader Bill Shorten will on Friday reveal Labor's policy is to aim to slash carbon emissions by 45 per cent by 2030 and offset Australia's CO2 pollution by the middle of the century.

"For the next election he wants people to think that he is Mr Green but, actually, he would have to introduce a carbon tax at twice the last rate and smashing household budget costs and costing jobs and growths," Mr Pyne told Nine's Today show on Friday.