Australia's federal government will soon have to tackle the over-centralisation of power within Australia's grocery market sector, Nationals' senator-elect Barnaby Joyce says, according to a report carried by Australian Associated Press.

Farmers, particularly in the horticultural sector, were at a serious disadvantage because the retail sector was dominated by just two buyers - Coles and Woolworths, Joyce said.

Farmers' groups have expressed ongoing concern over the strength of Coles and Woolworths, with particular concern that farmers can lose their contracts if they openly complain about the situation.

Mr Joyce said farmers were extremely worried about the power of the two retail giants. "I think that people out there ... they feel that there is an over-arching power in the current Coles-Woolworths setup that affects the way they trade in the market," he told ABC radio.

"They have problems, they feel they're threatened, they feel that they don't get a fair price, but they know that it's the only price they're going to get because Coles and Woolworths are the major purchaser of their product," he said. Joyce said it was clear there was too much power in the hands of the retailers, and not enough redress under the Trade Practices Act for farmers.

He said the government had to start looking at beefing up the act to help small businesses.

"I think we have to put basically everything on the table," he said. "We have to start putting on the table the way we're going to actually redress it."

Mr Joyce said the current debate was too focused on what constituted a centralised retail sector.

He said with Coles and Woolworths controlling between 75% and 83% of the total retail market, there was no argument. "It is a portion of the retail market that is not matched anywhere else in the world," he said.