Greek shares are flat in morning trading, as investors await the details of a last-minute compromise proposal from Athens to break a deadlock with European creditors over Greece's frozen bailout program.

Government spokesman Gavriil Sakellaridis says Greece is doing everything it can to reach a speedy and mutually acceptable deal with the other 18 European countries that use the euro currency.

But he insisted, speaking to private Skai TV, that the new radical left-led government would not accept further austerity measures to secure continuation of the bailout support Greece badly needs.

Eurozone finance ministers have given Greece until Friday to request an extension of its current austerity and reform program.

The weeks-old government in Athens is expected to submit a proposal Thursday for extension of the loans, without further austerity.