The amended code is contained in a draft order put out for consultation this week by the Competition Commission, which said the "strengthened and extended" code would result in a "major improvement to relationships between retailers and suppliers".
Inquiry chairman Peter Freeman said the code would prohibit retrospective changes to terms and conditions and limit the extent to which suppliers were required to pay for listings, promotions, inaccurate forecasts or customer complaints.
However, commentators have questioned its impact without an enforcement officer in the shape of an ombudsman. "A strengthened code will only work if it is accompanied by a robust and proactive enforcement mechanism," said an NFU spokesman.
The commission said it would be consulting publicly in the next couple of weeks on the establishment of an ombudsman.
However it does not have the power to establish an ombudsman itself and will have to gain agreement from the major retailers or refer the issue to the Government.
The commission also said this week that an order outlining measures to prevent exclusivity arrangements and restrictive covenants being used by grocery retailers would be published shortly.