By Lefteris Papadimas and Michele Kambas ATHENS (Reuters) - Greek lawmakers bickered through the night over a new bailout deal to keep the country afloat, only hours before euro zone finance ministers are due to decide on Friday whether to approve the vital aid for Athens. With the ruling Syriza party apparently heading for a split over the 85 billion euro ($95 billion) programme, parliament finally began debating whether to accept the package which demands yet more austerity and economic reform at 3:45 a.m. (0045 GMT), with no vote likely until well after daybreak. Parliament is expected to approve the agreement with Greece's euro zone and International Monetary Fund creditors by a comfortable margin when it finally votes, since opposition parties have promised to back Prime Minister Alexis Tsipras to ensure that Greece does not return to financial chaos.