BUENOS AIRES, April 19 (Reuters) - Argentina's government said on Wednesday grain exporting firms have again been allowed more time to reschedule wheat shipments without penalty, as it seeks to prioritize local supply after a historic drought shrunk the crop.

The temporary extension, authorized by the agriculture secretariat, was published in the government's official gazette. It is set to impact supply from Argentina to global markets.

Potential exports have been allowed a 360-day extension "with the start of shipment between December 1, 2022 and July 31, 2023."

Argentina's 2022/2023 wheat harvest reached just 12.6 million tonnes, down 43% compared to the 22.1 million tonnes farmers produced during the previous harvest.

The drought, which ran from May 2022 to March 2023, hit the country's major farm exports, including wheat, corn and processed soybeans, which are all key sources of foreign reserves for its cash-strapped central bank.

The government's previous extension, which was granted in November, covered sales with shipments beginning in the first two months of the year. (Reporting by Maximilian Heath; Editing by Muralikumar Anantharaman)