THE most ambitious greenhouse gas target flagged by the government - a 25 per cent cut by 2020 - is achievable at a cost to households of less than $4 a week, a detailed study has found.

It challenges claims that tackling climate change would trigger an exponential rise in the cost to consumers.

ClimateWorks Australia, a partnership between Monash University and the philanthropic Myer Foundation, examined the size and cost of potential emissions cuts in 54 areas. It found nearly a third of the cuts would save the community money, largely through improved energy efficiency in commercial buildings, industry and transport. The savings could help offset the expensive transformation of the electricity sector from ''dirty'' coal to cleaner energy forms.

ClimateWorks executive director Anna Skarbek said the cut would require a carbon price, as proposed by the government, and targeted ''direct action'', championed by the opposition.