* Argentina restricts wheat exports to ensure local supply

* Source says ships arriving this week to pick up wheat

* Brazil mills fear Argentina to curb wheat exports (Adds details on shipment, quote, context on Argentine wheat)

BUENOS AIRES, Dec 18 (Reuters) - Argentine exporters arestill awaiting the government’s green light to ship 1.6 milliontonnes of 2013/2014 wheat that has already been sold, a sourcefrom the local agricultural market said on Wednesday.

International markets are anxiously waiting for word of whengrains powerhouse Argentina will start exporting wheat, whoseinternational sales are regulated to ensure domestic foodsupply.

“We’re waiting for them to give us a date to be able toship, because the ships coming to pick up the wheat are arrivingthis week,” the source, who asked to remain anonymous because itis not authorized to speak to the press, told Reuters.

“There was a meeting to see when the delayed shipments couldbe made and it seems it could be solved in coming days,” thesource added. “If not, Argentina is going to lose the Brazilianmarket, which needs wheat right now.”

Brazil, the main export destination for Argentine wheat, hasstarted to seek out wheat from other producers on fearsArgentina is restricting exports, traders said on Wednesday.

Argentina’s Agriculture Ministry wasn’t immediatelyavailable to comment.

The 2013/14 wheat crop should come it at 8.5 million tonnes,the ministry said earlier this month. Argentina’s domesticmarket will require an estimated 6.5 million tonnes.

It remains unclear if around 2 million tonnes of wheat willreceive authorization to be exported. But 1.6 million tonnes ofwheat have been cleared for export, the source said, though theystill need permission to ship.

Local farmers are avoiding wheat planting to skirt exportcurbs that the government puts on wheat and corn. Growers saythe curbs hurt profits by killing competition among buyers whobid for their crops.

Brazilian mills have purchased 50,000 tonnes of U.S.-originwheat as short-covering on fears about Argentina supply,European traders said. (Reporting by Maximilian Heath; Writing by Alexandra Ulmer;Editing by Gerald E. McCormick and Phil Berlowitz)