Greece will sell almost all of its stake in gambling monopoly OPAP, the government has said.

This will increase the amount that is for sale in an attempt to convince foreign lenders that it is serious about selling off state assets.

Athens, which owns 34% of one of Europe's biggest gaming companies, has launched a tender to sell a 33% stake in the company, the privatisation agency HRADF said.

Previously Greece had planned to sell 29% of OPAP, currently worth about €450m on the Athens bourse.

OPAP is central to Greece's plan to raise €19bn from privatisations by 2015 - a key condition of its €130bn bailout agreed earlier this year.

It is the country's most profitable state firm with a sports betting monopoly stretching, for some games, as far as 2030.

Greece is badly behind on privatisation targets and the three-month-old, conservative-led government has pledged to do better as it struggles to convince the EU and the IMF to resume the bailout payments that keep the country afloat.

"The fact that OPAP is being completely sold off shows the government's will to privatise," said Dimitris Mardas, an economics professor at Thessaloniki's Aristotle University.

HRADF set an 19 October deadline for expressions of interest and said the tender would be carried out in two phases.

After an initial declaration of interest, bidders will be called to submit binding offers, HRADF said.

The agency has the right to introduce an intermediary phase of non-binding bids in order to evaluate bidders' business plans.

"The complete privatisation of OPAP will be carried out transparently, rapidly and with efficiency," HRADF's chief executive Yiannis Emiris said in the statement.

A senior government official told Reuters earlier this month that Athens aimed to find a buyer for OPAP by January and that four consortia of Greek and foreign companies were interested in the company.

Turkish conglomerate Dogan Holding said on Monday it would consider taking part in a sale tender for OPAP. Investment funds Fidelity and Silchester Inv. already hold 5% each in the company.

Greece has picked Deutsche Bank and National Bank of Greece as financial advisers, it added.

Athens has already moved to clear issues that might block the company's sale.

Earlier this month, it settled a row with European Union competition authorities over how the company should be taxed and set a new 30% levy on gross earnings from next year.

But investors' appetites might be dampened by an ongoing court challenge against the Greek company's monopoly brought by Britain's biggest bookmaker William Hill and online gaming companies SportingBet and StanleyBet after they were denied gambling licenses in the country.

A senior EU legal adviser raised questions about OPAP's right to control all betting in the country last week.

Greece's highest administrative court is expected to issue a final ruling on the case in the coming months.