ATHENS - Europe's biggest betting firm, OPAP, said on Tuesday it had renegotiated a binding sales agreement with sales agents in Greece, a move that will help shield it from any possible deregulation of the Greek gaming market.

OPAP has the exclusive right to offer lotteries and sports betting games in Greece, through a disparate network of about 5,300 agents, until 2020.

The Greek government has yet to officially decide on whether to deregulate the gaming market, however the European Commission has launched an infringement procedure against Greece over the country's gaming law.

In recent years, OPAP has been losing market share in Greece's lucrative 2.3 billion euros ($3.22 billion) sports betting market to internet rivals, in spite of the fact that online betting is illegal in Greece.

The new agreement ties up the agents with OPAP and opens the way for the firm to restructure its network and give it a uniform look, OPAP said in a statement.

All our actions (are) aimed at ensuring OPAP's long-term growth. The new contract with the agents sets up a mutually advantageous framework of cooperation, OPAP's Chief Executive Christos Hadjiemmanuil said in the statement.

Analysts said the deal protects OPAP from the possibility of betting market deregulation in Greece and gives the lottery a tighter control over its network, replacing a previous, vague framework regulating its relations with the agents.

If the market opens tomorrow, it will be more difficult for an agent to break away and join a competitor, Proton Bank analyst Nikos Lianeris said.

At 1142 GMT, OPAP shares were up 5.6 percent to 19.60 euros on the Athens bourse .ATG, which was up 2.57 percent.

The stock trades at 8.17 times its estimated 2009 earnings compared with a multiple of 9 for British bookmaker William Hill (WMH.L), according to Reuters Estimates. ($1=.7143 Euro) (Reporting by Angeliki Koutantou; editing by Simon Jessop)