ATHENS (Reuters) - Greece might never have secured an agreement on a third bailout from its creditors without Washington's help, Deputy Prime Minister Yannis Dragasakis said on Wednesday, as his government prepared for a crucial vote in parliament on reform measures.

"I have to publicly thank the U.S. government and Mr. (President Barack) Obama as without their help and persistence that the deal has to include the debt issue and development horizon we might have not succeeded," he said.

An International Monetary Fund study published on Tuesday showed that Greece needs far more debt relief than European governments have been willing to contemplate so far, as fractious parties in Athens prepared to vote on a sweeping austerity package demanded by their lenders.

(Reporting by Lefteris Karagiannopoulos; writing by Matthias Williams; editing by Costas Pitas)