ATHENS (Reuters) - Greece's privatization agency (HRADF) has invited OPAP (>> Greek Org of Football Prognostics S.A.) to sign a deal next week to acquire the country's sole license for horse racing betting, the first state asset sale to be completed by the new leftist-led coalition government.

The agency announced in March it would proceed with the sale of the exclusive betting rights to OPAP, the country's dominant gambling firm, which won the license last year after offering 40 million euros ($43.26 million).

"HRADF...invited the successful bidder, OPAP Ιnvestments Ltd, to sign the concession contract on April 24," the agency said in a statement on Friday.

Betting on horse racing in Greece had been run by a state-owned group.

Greek Prime Minister Alexis Tsipras told Reuters on Thursday that state assets were one of the thorny issues in talks with the EU/IMF creditors assessing whether the cash-strapped country can get further bailout aid.

Privatizations have been a key demand of the country's international lenders. The election of Tsipras' government in January on promises to end austerity and block "fire-sales" cast doubt on the future of Greece's privatizations plan.

Greece has a series of ongoing tenders for the divestment of state assets, including the sale of a 67 percent stake in its biggest port Piraeus and the lease of a bundle of 14 regional airports to a joint venture led by German airport operator Fraport (>> Fraport AG Frankfurt Airport Srvs Wrldwd).

In a reform list sent to the creditors last month, Athens estimated privatization revenues of 1.5 billion euros this year.

The government has made clear that it will honor all existing contracts.

It has also said that it favors joint ventures and wants the state to keep a minimum stake in its assets to boost social security funding and protect workers' labor rights.

(Reporting by Angeliki Koutantou; Editing by Keith Weir)