The path toward a long-term deal on Greece's bailout will look like a "rugby scrum," the chief debt negotiator during the Greek financial crisis told CNBC on Monday, invoking the image of two adversaries fighting in close quarters for mere inches of progress.
"We are likely to see more brinkmanship. I'm afraid that we're going to see continued volatility and uncertainty surrounding Greece for quite some time. This is not over yet," Charles Dallara said in a "Squawk on the Street" interview.
Greece will present its economic reform plans on Monday to seal a euro zone financial lifeline, but the government drew criticism from a veteran leftist and ruling party member that the deal let voters down.
The request that Greece submit detailed proposals by Monday—part of an agreement reached Friday to extend the bailout for four months—was "a little bit premature" and will set up the scrum, said Dallara.
The question is whether it leads to a more balanced and effective reform program for Greece.
Dallara led the Institute for International Finance's effort to bring Greece and its private creditors to a March 2012 agreement that concluded with the largest voluntary debt restructuring in history.
Germany, the biggest contributor to Greece's two bailouts totaling 240 billion euro, said any extra spending on Athens' list of reforms had to be offset by savings or higher taxes.
After a climbdown in Brussels to win the conditional four-month agreement, the government of Prime Minister Alexis Tsipras declared the reform list would at least be decided by Greeks, in contrast to the austerity policies dictated by foreign creditors since they bailed out Athens in 2010.
Tsipras has declared victory in Friday's deal, which is conditional on Greece's European and IMF creditors accepting the reform list, even though he had to accept an extension of the bailout program he had promised to scrap.
The measures, which the Eurogroup of euro zone finance ministers will consider in a teleconference, aim to raise revenue in ways favored by Tsipras's leftist Syriza party, such as taxing the rich and tackling tax evasion and graft.
Following a series of Eurogroup meetings, the international creditors will scrutinize the reforms to ensure they comply with another Greek concession—that nothing Greece does during the four months burdens the state budget.
Greeks have a legitimate case for seeking more flexibility on the fiscal front, Dallara said, and despite some European leaders' hard line, he believes they will ultimately grant that flexibility.
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The key question, he said, is whether or not the government in Greece is prepared to accept a recommitment to structural reforms that are needed in the country. That remains unclear, he added.
For their part, Europeans will have to be prepared to accept somewhat lower interest rates and longer maturity periods, he said, but there is no doubt that an actual writeoff of Greek debt is now off the table.
Reuters contributed to this report.