The NFU described the plan as "a victory for common sense and the consumer" and said it followed ten years of NFU lobbying for a fair and transparent supply chain.
NFU president Peter Kendall added: "We've worked incredibly hard to make this a reality and we can at last see light at the end of the tunnel. When the new strengthened code comes into force we need a proactive and robust enforcement mechanism in place as soon as possible.
"This current investigation into the grocery market began in 2006. 2010 must be the year in which we begin to eradicate unfair dealing and protect investment and innovation in British agriculture for the benefit of farmers and growers as well as consumers."
The Forum of Private Business (FPB) said it welcomed a supermarket watchdog but stressed that more is needed to help small suppliers who may be reluctant to complain about their poor treatment for fear of losing supermarkets' business. A guarantee of anonymity in complaints could address this problem, it suggested.
FPB chief executive Phil Orford said: "Small suppliers and retailers continue to suffer as a result of supermarkets' anti-competitive practices. One of the main problems is that many suppliers feel intimidated into silence."
He added: "While a dedicated watchdog for these businesses is welcome, it does not go far enough to hold large retailers to account or to address the need to reinvigorate small shops on our high streets and the communities they serve."