New research shows it could cost $15 billion per year to meet a target of cutting New Zealand's greenhouse emissions by 40% by the year 2020.
A goal of 40% is urged by Greenpeace for adoption by New Zealand before a UN summit in Copenhagen in December on a successor to the 1997 Kyoto Protocol.
The Institute of Economic Research and Infometrics looked at four scenarios on behalf of the Government.
They calculated that a cut in emissions of 40% will cost around $3000 per person by 2020.
Based on estimated population growth by then, the study suggests this would amount to a cost of around $15 billion to the economy.
Another scenario, for a cut of 15%, would cost around $1400 per person.
Public consultation on a Government target for 2020 emissions closes at the end of this week.