Australia could meet almost half of its 5 per cent greenhouse reduction target by ending logging of native forests, according to a new economic study.

The report, by Australian National University climate law expert Andrew Macintosh, estimates ending logging would generate enough carbon credits to meet 45 per cent of Australia's emissions reduction target. In order to meet the 5 per target, Australia will need to reduce its carbon emissions by 152 million tonnes by 2020.

"It's one of the fastest and cheapest ways for Australia to cut its emissions," Mr Macintosh said.

The ANU study is the first to calculate the potential carbon credits Australia could generate over the next eight years by reducing, or ending, native forest harvesting.

It found keeping native forest harvesting at current levels would generate credits equivalent to 12million tonnes of carbon, or 14 per cent of Australia's total abatement target.

Reducing harvesting to 50 per cent below 2002-09 average levels would generate credits worth 19 million tonnes, or 22 per cent of the 5 per cent target. "These are substantial figures, but the critical policy question is whether this is the most cost-effective way for Australia to meet its mitigation target," Mr Macintosh said.

According to the study, native forests are "now responsible for only a minority of wood production", with harvesting falling by 41 per cent from 11 million cubic metres a year to 6.5 million.

The study comes as a $276 million Tasmania forestry deal signed by Prime Minister Julia Gillard and Tasmania's Premier Lara Giddings continues to meet opposition from business, industry and environmental groups.

The package offers $85 million to support forestry workers and their families affected by a plan to protect 430,000ha of high conservation forests as reserves or national parks.

The Federal Government will provide $43 million to manage these areas, and $120 million will be allocated to establish new industries, such as forestry tourism, in affected towns.

Tasmanian Chamber of Commerce and Industry chief executive Robert Wallace has dismissed the deal as pandering to Greens voters "in the trendy cafes of Melbourne and Sydney".

"If we had to live on forest tourism income alone, we would be poorer than Papua New Guineans. Tasmania does have a great future in tourism, but not at the expense of other industries and opportunities," he said.

Tasmania's acting Premier Bryan Green said yesterday the state Government would not be swayed by "vested political interests" trying to undermine the agreement.

Mr Green said the agreement would allow those workers affected by the timber market downturn and a recent decision by Tasmanian timber company Gunns to quit native forest harvesting "to leave the industry with dignity".

He said the Government would restructure the state's forestry industry and use federal funds to benefit regional communities.

"There are forest workers counting on the Government to deliver this agreement and we will not let them down," he said.