A customer choosing edible oil at a supermarket in Zhengzhou, Henan province.[China Daily]

The source said the new norms could help increase shipments of soybeans and soybean oil from countries like the United States and Brazil. At the same time it may also lead to a decline in imports from Argentina.

Earlier reports said a Chinese trade body had asked traders to stop buying soybean oil from Argentina, the world's largest soymeal supplier.

"It is far from true. China has not asked the traders to stop buying edible oil from Argentina. What we did was to tweak the quality standards, for imports as our studies found that Argentine soybean oil contained excessive solvent residues," said a source from the China Chamber of Commerce of Import & Export of Foodstuffs, Native Produce & Animal By-Products (CCCFNA).

Imports from Argentina will certainly decline if the country refuses to adhere to the quality norms, the source said on condition of anonymity.

The CCCFNA is affiliated with the Ministry of Commerce, which supervises and manages the trading activities of the domestic edible oil industry.

On March 31, MOFCOM, at a conference of major traders, said the solvent residues used for processing soybean oil should not exceed 100 parts per million (ppm). The solvent residue level in soybean oil imported from Argentina was around 300 ppm.

MOFCOM and the General Administration of Quality Supervision, Inspection and Quarantine, however, did not respond to the queries posed by China Daily on the issue on Tuesday.

Argentina's foreign minister Jorge Taiana has conveyed his discomfort and concern over the development to Gang Zeng, China's ambassador to the South American nation. It has also sent a high-level team of agriculture officials to China for more consultations on the issue.

"China's imports are of tantamount importance to Argentina. The new rules will derail Argentinean exports, and help the US and Brazil," said Lief Chiang, an analyst with Rabobank Shanghai.

Nearly 70 percent of the soybean oil imported by China comes from Argentina, followed by the US and Brazil. China is also big importer of soybeans. In 2009, it bought 42.55 million tons of soybeans and 4.6 million tons of soybean oil.

Sources from Argentina, however, maintain that the new quality norms are impossible to adhere to and unachievable by any country, according to Reuters reports.

Argentina sells more than 40 percent of its soybean oil to China, more than 2.5 times the amount it sells to India, its next biggest customer. The new norms, when applied, will reportedly lead to a loss of more than $600 million for Argentina.

Analysts said China's measure is also probably a response to the growing trade remedy cases by Argentina against China during the past year, covering shoes and steel pipes.

"China should have taken such retaliatory measures much earlier, as the South American nation was aggressive and unreasonable while banning Chinese exports," said Wu Guoping, a senior researcher from the Latin-American Institute of the Chinese Academy of Social Sciences.