Retailers and processors have a 'moral responsibility' to support British farmers by promoting cuts of meat in stores as many face disruption due to Covid-19.
Promoting steaks and roasting joints, which are now in high supply due to the complete loss of the food service market, could boost farmers, NFU and NFU Cymru said.
In an open letter, NFU livestock board chairman Richard Findlay and vice-chairman Wyn Evans said that the supply chain should act in the interests of both consumers and farmers.
They reiterated that British beef and lamb is in plentiful supply but warned that ongoing high demand for products such as mince would soon become unsustainable.
In the letter, they said beef and sheep farmers are facing 'massive and unwarranted disruption' to their livelihoods as a result of the coronavirus outbreak.
"But while consumers continue to demand high quality beef and lamb, which farmers can supply, we see unsustainable returns for our livestock that are undermining the moral partnership needed between farmers, processors and retailers," the letter reads.
“It’s clearly a national priority to ensure shoppers can feed their families and keep the nation going at this time of need.
"The farmers we represent feel passionately about contributing to this effort and we want to make sure that you and your customers are assured that British beef and lamb is in plentiful supply."
Buying patterns in retail have caused significant problems with products like steaks and joints being outsold and out of balance by mince.
But Mr Findlay and Mr Evans said beef and sheep producers 'cannot sustain a stable supply of one half of each animal'.
They added the whole chain has a 'renewed moral responsibility' to make sure they market and value products 'responsibly' to avoid disruption to the consumer and farmers’ ability to maintain supply.
“We are urging all retailers to take stock in this period of uncertainty and reconsider their responsibility to their suppliers in this newly constrained marketplace," the letter reads.
For beef and lamb, that means buying in balance and ensuring farmers receive a sustainable return.
“We are encouraged to see some retail lines promoting those prime cuts such as steaks and roasting joints as Easter and the warmer weather approaches.
"All the farmers we represent want to help you help the nation through this crisis, we do however need all retailers to play their part with us,” Mr Findlay and Mr Evans said.
The NFU said it will be contacting all retailers separately to understand individual plans to deal with the disruption in supply.