ABU DHABI, June 12 (Reuters) - Egypt's state grain buyer, the General Authority for Supply Commodities (GASC), said on Friday it had bought 180,000 tonnes of Russian and Romanian wheat in a tender for July 11-20 shipment.

Egypt, the world's biggest importer of wheat, bought 60,000 tonnes of Romanian wheat from Bunge, another 60,000 tonnes of Romanian wheat from Nidera and 60,000 tonnes of Russian wheat from Aston, said GASC vice chairman Mamdouh Abdel Fattah.

The wheat was purchased at an average price of $200.72 a tonne on a cost-and-freight basis, he said.

Traders gave the following breakdown of the purchase:

* 60,000 tonnes of Romanian wheat from Bunge at $192.16 a tonne free-on-board (fob) and $8.29 a tonne freight from Venus

* 60,000 tonnes of Romanian wheat from Nidera at $192.16 a tonne fob and $8.60 a tonne freight from National Navigation

* 60,000 tonnes of Russian wheat from Aston at $191.98 a tonne fob and $8.99 a tonne freight from National Navigation

It GASC's second tender in two days after the agency bought 60,000 tonnes of Russian wheat from Louis Dreyfus on Thursday for the same shipment period.

Apart from purchases on the international market, Egypt has bought a record 5.275 million tonnes this local procurement season which started mid-April and is due to end on Monday.

The supply ministry said on Thursday that Egypt's strategic wheat reserves were enough to last until Dec. 22.