Rains that fell over much of Argentina's agricultural areas have improved conditions for soyabean and corn crops in the major grains exporting South American country, the Buenos Aires grains exchange said in its weekly report on Thursday.

The crops, which are both deep into the planting season, have been contending with dry weather that had threatened to hit output at a time when Argentina's economy sorely needs its major grains sector firing on all cylinders.

Argentina is the world's top exporter of soyabean oil and meal, and the third largest in corn. The grains exchange maintained its estimates for soya planting at 17.7 million hectares and for commercial corn at 6.3 million hectares.

"Rains since our previous report improved water reserves in a large proportion of the lots," the Buenos Aires exchange said.

The exchange said 84.3% of soyabeans had been planted, while planting of corn was 83.5% complete. With more advanced wheat, 92% of the planted area for the 2019/20 season had been harvested, with production expected at 18.5 million tonnes.