Europe Economy

IMF: Greece needs to reform for sustainable debt, financing needs rising

Mark Wilson, Getty Images News

Greece's debt dynamics are "unsustainable," and the country needs to get serious about reforms if it hopes to fix the situation, according to an analysis released Thursday by the International Monetary Fund.

The fund—a major institutional creditor to Athens—has long called for Greece to adhere to a strict reform program, but the left-wing government has resisted, and ended up missing its June 30 debt repayment of about 1.55 billion euros to the IMF. The institution warned that the country may require a debt writedown without sufficient reform and strong growth.

The situation is so bad for Greece, the analysis said, that the government needs about 51.9 billion euro between October 2015 and December 2018. And the economic position has worsen: Last year, the IMF predicted Greece's debt would fall from 175 percent of economic output in 2013 to 128 percent in 2020. Now it sees Greece's debts at 150 percent in 2020.

Read MoreGreek latest: Europe warns of 'no' vote consequences

Furthermore, the IMF said that even if Greece had the highest participation rate in Europe, the lowest unemployment rate and average productivity gains, the economy would still grow at less than 1 percent a year.

The analysis addressed the need for reform in Athens.

"To ensure that debt is sustainable with high probability, Greek policies will need to come back on track but also, at a minimum, the maturities of existing European loans will need to be extended significantly while new European financing to meet financing needs over the coming years will need to be provided on similar concessional terms," the IMF said.

"But if the package of reforms under consideration is weakened further—in particular, through a further lowering of primary surplus targets and even weaker structural reforms—haircuts on debt will become necessary," it added.

Read More Investor: Will Greece be a 'Lehman moment' for markets?

Such a move could even include a "full write-off of the stock outstanding in the GLF facility (€53.1 billion) or any other similar operation," the report said.

Only with the "full and decisive" implementation of structural reforms, then Greece could potentially see growth of up to 2 percent in the medium- to long-term, the analysis said.

The analysis was drafted before Greece imposed capital controls and missed its IMF payment, the document said.

—The Associated Press contributed to this report.