FARMERS are still skeptical about the Federal Government's carbon tax despite fuel for households and small businesses being exempt.

Victorian Farmers Federation president Andrew Broad said farmers were waiting for more information about the tax but many remained concerned about the impact the tax would have on rural communities.

"The claim by the Prime Minister that exempting petrol for households and small businesses is somehow a major win for rural Australia is yet to be clarified," Mr Broad said.

"While we'd like more detail on diesel fuel, it appears producers will still be in the tax man's gun when it comes to transporting our products to market. Including diesel in a carbon tax would significantly push up the price of food given the role of transport as one of the key components of the supply chain," he said.

Research released by the National Farmers Federation and Cattle Council of Australia predicts if fuel in agricultural production is included in the tax scheme, beef producers will face about $7000 in extra costs each year, if the price is set at $35 a tonne.

"The announcement that petrol will be excluded from the proposed carbon tax may be good news for families, but it is not clear what impact the decision will have for farmers," NFF president Jock Laurie said.

The Gillard Government plans to announce the carbon price this Sunday.

In a statement Prime Minister Julia Gillard said additional discussions with the Multi-Party Climate Change Committee will nut out further details before Sunday's announcement.