Euro zone officials have said it will be hard for Athens to make the budget numbers add up without a forecast 4 billion euros due from the sale of state assets this year and savings through later retirement and a merging of pension funds.
However, both reforms are bitterly opposed by Tsipras' leftist Syriza party, and ministers have already halted several planned privatizations.
Greece is also hoping to secure another 1.9 billion euros in profits made by the European Central Bank on past purchases of Greek government bonds, but the euro zone has tied that to approval of its reforms by the institutions representing its main creditors - the International Monetary Fund, the ECB and the European Commission.
Commission President Jean-Claude Juncker told the European Parliament he had been "very pessimistic" about Greece in recent weeks but now believed its bailout process was back on track.
Read MoreDéjà vu? Greece crisis talks but nothing's changed
"I have to recognize that I was very pessimistic during the last weeks because there was no progress whatsoever," Juncker told the European Parliament.
"But now we are back in a normal process and I do think that we can come to a conclusion that will be both in favor of Greece - we love Greece - and the European Union," he said.
The ECB slightly loosened its leash on Greek banks on Wednesday, increasing the amount of emergency cash they can borrow from the Greek central bank to above 71 billion euros, from 69.8 billion previously, a banking source said.
However, wearing its other hat as the euro zone's banking supervisor, the ECB ordered Greek banks in a letter not to increase their holdings of short-term government debt.
ECB chief economist Peter Praet called on policymakers to exercise more "verbal discipline" on Greece to avoid stoking already high political and market tensions.