CAIRO, May 26 (Reuters) - Egypt has extended its tender for natural gas exploration in the Mediterranean Sea by two months with the addition of four new blocks, the state gas board said on Tuesday, as the country seeks to boost domestic energy production.

The bidding period now runs to July 30 and will include 12 offshore concessions instead of eight, the Egyptian Natural Gas Holding Company (EGAS) said in a statement.

Egypt is going through its worst energy crisis in decades, with increasing consumption and declining production turning the country from a net energy exporter to a net importer over the past few years.

The north African country has tried to tackle energy shortages by raising energy prices, building new power plants, importing liquefied natural gas (LNG) and encouraging more domestic oil and gas production.

EGAS did not give any reason for the tender extension, but Egypt similar moves have been made in the past when there was not enough interest or when potential bidders requested more time to complete evaluations.

The four additional blocks are Northeast Habi Marine, North Farma Marine, North Tabiya Marine and Northeast Amiriya Marine, EGAS said.

The original eight blocks are West Arish Marine, East Port Said Marine, North Rumana Marine, North Ras al-Ash Marine, West al-Timsah Marine, South Taneen Marine, North Hammad Marine and East Alexandria Marine.

The twelve blocks together cover a total of 20,548 square kilometres (7,934 square miles).

The foreign companies already exploring for oil and gas off Egypt's north coast include Italy's ENI ENI.MI and Britain's BP BP.L and BG BG.L .

(Reporting By Ehab Farouk; Writing by Shadi Bushra; Editing by David Goodman) ((shadi.bushra@thomsonreuters.com; +20 109 353 8134; Reuters Messaging: shadi.bushra.thomsonreuters.com@reuters.net))

Keywords: EGYPT GAS/TENDER