A US ruling to warn drug companies that antibiotics given to livestock could be banned has been welcomed.

According to The New York Times a US judge warned the Obama administration last month to warn drug makers that the government may soon ban agricultural uses of some popular antibiotics that many scientists say encourage the proliferation of dangerous infections and imperil public health.

"The practice of feeding antibiotics to promote growth has led to a judge's order that moves towards ending that use of the drugs," the newspaper said.

In a separate move earlier this month the US Food and Drug Administration has called for a substantial reduction of the use of antibiotics.

The FDA singled out the widespread practice of using antibiotics to spur growth in food-producing animals and said it has to be phased out within three years, but left it to the drug and livestock industries to comply voluntarily.

"We know that the widespread use of antibiotics can contribute to antimicrobial resistance, which has public health consequences," FDA deputy commissioner for foods Michael Taylor said.

Farm animals in the US consumed 29.1 million pounds of antibiotics in 2010 according to the latest data.

In one of two reports the FDA is instructing drug companies to remove growth promotion as a valid use for antibiotics that are primarily given to livestock through feed.

Mr Taylor said the FDA would consider further action if the livestock and drug industries did not comply.

Biological Farmers Australia convenor Andrew Monk said a ban would be a positive move.

"Incorporating antibiotics into animal feed is not only damaging the use of antibiotics in human use, but is not managing human health correctly," Dr Monk said.

"The use of antibiotics in animal feed is plastering over a structural issue for a broader issue.

"Consumers who want truly free range in addition to artificial additive- , antibiotic- and synthetic agrichemical-free, should look for the recognised and respected Organic Bud logo with the words '‘Australian Certified Organic' to be assured they are buying what the label claims."

Under the Australian Certified Organic Standards incorporating antibiotics in feed is prohibited.

- With staff writers