The government will "intensify" its lobby against "stunting" food tariffs, President Jacob Zuma says.

"As government, we will continue to intensify our lobby internationally, against the food and safety standards, tariff and subsidy measures imposed by the Organisation for Economic Cooperation and Development," Zuma said at the start of a three-day farm worker summit in Somerset West outside Cape Town.

"These measures stunt growth in our emerging economies."

Zuma said an improved international trade regime "will improve the country's bargaining power globally".

Spinoffs to the agricultural sector will "filter down" to farm workers, he said, adding that there was still some room to increase the three percent that agriculture contributed to the gross domestic product.

Agricuture, Forestry and Fisheries Minister Tina Joemat-Petterson told the summit that tariffs were skewed against farmers.

"They favour cheap agricultural goods to be imported into our country," she said.

"It is the workers and the farmers who suffer.

"It is a vicious cycle that we have to break."

She said the government's objective was to have "market related" development of emerging farmers".

"Farmers can not be emerging forever.

"A seed doesn't take 16 years to grow," she said.

"We have to look at the commercial side of agriculture. Our objective is to have market related development."

AgriSA president Johannes Moller told the conference that "agriculture can earn a lot more forex than it does at the moment".