CAPE TOWN (Reuters) - South Africa will relax some of its tough rules on genetically modified crops so it can ramp up maize imports from the United States and Mexico to avert a potential food crisis amid a severe drought, officials said.

A hawker prepares a cob of corn at his makeshift shop in Soweto, in this January 27, 2016 file photo. REUTERS/Siphiwe Sibeko/Files

Almost 90 percent of maize in South Africa is genetically modified and the country bans commodities with strains not approved by the government and does not allow imports to be stored, stipulating they must be transported immediately from ports to mills.

Makenosi Maroo, spokeswoman at the Department of Agriculture, told Reuters on Tuesday that the government planned to permit importers to temporarily store consignments of GM maize at pre-designated facilities, to allow much bigger import volumes.

“In anticipation of the volumes expected to be imported into South Africa, the (GMO) Executive Council has approved the adjustment of a permit condition which relates to the handling requirement,” Maroo said.

“There is therefore no intention to relax safety assessment or risk management procedures prescribed.”

The government, however, has not said when the rule changes would come into effect or whether they would be permanent.

The worst drought in a century has scorched vast swathes of croplands, affecting around 2.7 million homes in Africa’s most advanced economy where shortages of white maize - a staple food for the black majority - could reach crisis proportions by October if expected summer rains do not fall, analysts say.

The country needs to import about 1.2 million tonnes of white maize and 2.6 million tonnes of yellow maize, according to the government, based on the current conservative domestic crop estimate of 7.4 million tonnes, with only Mexico and the United States able to plug the shortfall.

South African maize producers called for much more far-reaching rule changes to cope with the situation. Maroo said the government was also considering applications to register additional GMO varieties that would boost maize trade between the United States and South Africa.

The South African National Seed Organisation, which represents firms such as Monsanto and DuPont Pioneer, said it has six such applications pending approval.

Advocates for GM crops argue it boosts yield and productivity in tough climate conditions and pestilence-prone regions, but critics say its effects on humans and the environment remain unproven.

As U.S. crops have significantly higher numbers of GM strains, fears of contamination during handling means suspect cargoes could be rejected as illegal at South African ports due to a “zero tolerance” policy.

“We want the zero tolerance regulation changed to at least one percent; to have it relaxed and help prevent bottlenecks occurring when we need to import,” Heiko Koster, a feed mill owner and member of the maize steering committee.

Most of the maize imports could come from the United States rather than Mexico because U.S. maize is cheaper and supplies more abundant, analysts said.