The National Farmers' Federation is frustrated that the Australian Competition and Consumer Commission's Grocery Price Inquiry has been unable to shine new light on the operations of the food supply chain and why primary producers' margins are being squeezed.

NFF vice president Charles Burke welcomed the ACCC as a start to the process, but said "farmers remain bemused as to why there is such a huge gap between what farmers are paid at the farm-gate and what consumers are charged at the checkout".

"Only a comprehensive review of the complete supply chain will help farmers and consumers to understand where the consumer dollar is going," Mr Burke said.

"That transparency is essential if any of us are to have confidence in retail pricing."

The NFF's call comes despite the ACCC inquiry's terms of reference calling for analysis on the entire supply chain.

However, the NFF says the inquiry was focused too heavily on the retail sector.

"The ACCC report reinforces our view, with the actions of many within the supply chain remaining relatively ignored," Mr Burke said.

"Without identifying efficiency problems or market breakdowns along the supply chain, our concern now is that simply cutting prices or adding costs at the retail end will mean slashing, even further, what farmers are paid for their produce.

"Despite the ACCC's assurances, we also remain concerned about those products, such as beef, where retail prices have risen in recent years while farm-gate prices have stagnated or declined."

However, Mr Burke said the ACCC has recognised that farmers need written contracts to apply between all purchasers of horticultural produce - wholesalers, exporters, processors and retailers alike.