Greece and its international lenders were locked in marathon overnight talks to seal a multibillion-euro bailout deal on Tuesday, racing against a countdown to European Central Bank debt repayments falling due in days.

The indebted country is hoping to wrap up a deal for 86 billion euros ($94.75 billion) in fresh loans by Tuesday so it can get parliamentary and other approvals for aid to flow by Aug. 20, when a 3.2 billion euro debt payment is due to the ECB.

"We are going into the final round of talks, looking at the Memorandum of Understanding from beginning to end," a senior Greek government official said during a brief break in talks in Athens, referring to terms of the bailout accord.

The latest round of negotiations started early on Monday afternoon.

An agreement would mark the end of a painful chapter on bailout talks for Greece, which fought against austerity terms demanded by creditors for much of the year before accepting a deal under the threat of being bounced out of the euro zone.

After lengthy negotiations on Sunday and Monday, Greek Finance Minister Euclid Tsakalotos said talks were going "quite well" and was optimistic that an agreement will be reached soon.

"I don't know if it will be (Tuesday) morning, but soon means soon," Tsakalotos told reporters.

A senior Greek government official said dealing with a mountain of non-performing loans in the banking sector remained a sticking point. Athens wants to set up a "bad bank" to handle this, while creditors want non-performing loans bundled and sold to distressed asset funds.

Officials also said the two sides had yet to agree on setting up a sovereign wealth fund in Greece designed to raise 50 billion euros from privatizations, three-quarters of which would be used to recapitalize banks and to decrease the debt.

Both sides had agreed to deregulate the country's natural gas market, sources said.

Greek banks could get an initial capital injection soon after a bailout deal is clinched, as much as 10 billion euros, even before the ECB completes a stress test, a euro zone official said on Monday.

The official said a test may not be finished before October, but that it was recognized that Greek banks urgently need capital to normalize their operations.

Popular misgivings run deep in Germany, the euro zone country that has already contributed most to Greece's two bailouts since 2010, about funneling yet more money to Athens.

Berlin wants a deal that includes an ambitious budget plan, a credible privatization strategy and a sustainable pension reform, Finance Ministry spokesman Juerg Weissgerber said.

Greek officials have said they expect the bailout accord to be approved by Greece's parliament on Wednesday or Thursday and then be vetted by euro zone finance ministers on Friday, paving the way for aid disbursements.

The bailout pact will be voted on in parliament as one bill with two articles - one on the loan agreement and memorandum of understanding and the second on the so-called prior actions that must be completed for aid to be released, a separate Greek official said. The negotiations began on July 20.

The two sides have agreed to set a budget surplus target before interest payments of zero percent this year, and expect the economy to shrink between 2.1 percent and 2.3 percent, a Greek official told Reuters.

In addition, the sides had agreed to a baseline scenario of a primary budget surplus of 0.5 percent of gross domestic product in 2016, and a primary surplus of 1.0 percent of GDP in 2017. The same scenario projected a 0.5 percent economic contraction in 2016, before registering 2.3 percent growth in 2017.