ANKARA (Reuters) - Turkey’s main opposition party yesterday asked prosecutors to investigate last year’s sale of a stake in oil refiner Tupras, saying the government had failed to hold an open, transparent tender.

The move followed calls for more transparency in Turkish politics, which prompted opposition leader Deniz Baykal and Prime Minister Recep Tayyip Erdogan to reveal their personal wealth.

“We hope the chief prosecutor’s office completes this investigation (into the tender) in a speedy fashion,” the center-left Republican People’s Party (CHP) said in a statement faxed to Reuters.

A group of CHP deputies handed their request to the Ankara chief prosecutor’s office. The letter specifically criticized Erdogan and Finance Minister Kemal Unakitan for their handling of the sale.

The government sold a 14.76 percent stake in Tupras to foreign-based investors in February 2005.

The CHP said the decision had caused a loss of $750 million to the Turkish Treasury. A consortium led by Turkish conglomerate Koc Holding and including Royal Dutch Shell bought the remaining 51 percent stake in Tupras for $4.14 billion in a tender last September. Turkey’s top administrative court this month cast doubt over that sale by ordering a suspension of the privatization on a request from a labor union.