FARMERS have warned of massive economic disruption despite the Federal Government's move to delay its emissions trading plans.

The National Farmers' Federation said the bush could still be devastated, as a new study showed many farmers face big losses.

With close to two million Australian jobs dependent on agriculture, "we would face the very real prospect of an economy-wide shutdown," acting NFF president Charles Burke said.

Citing the impact of the economic crisis, Prime Minister Kevin Rudd this week said the government's Carbon Pollution Reduction Scheme would be deferred until July 2011.

The carbon price will be fixed for a year at $10 a tonne, then determined by the market, and there will be extra free permits for trade-exposed, emissions-intensive industries.

The Government's 2020 carbon reduction target also would be lifted - from a maximum of 15 per cent on 2000 levels to 25 per cent - if other countries did likewise.

"The worst global recession since the Great Depression means we must adapt our climate change measures but not abandon them," Mr Rudd said.

The government still intends making a decision in 2013 on whether agriculture will be part of the scheme from 2015.

Mr Burke said farmers were relieved with the delays, but he said the scheme "could still devastate the farm sector" because farmers would be unable to pass on extra costs to export markets.

Mr Burke said the Government should instead develop alternative market mechanisms to help farmers cut their emissions.

In a new study, the Centre for International Economics said all farms face big cash income slumps if they were brought into the scheme.

Commissioned by the Rural Industries Research and Development Corporation, the study found beef farmers could have $36,000 sliced from their bottom lines at a carbon price of $25 a tonne, or $72,000 at $50 a tonne.

Dairy farmers face profit slugs of between $23,000 and $47,000, while sheep and wheat farmers could lose $14,000 to $26,000.

Only horticulture was likely to escape with a minimal impact, the study found.