The abstention by Latin American states from the IMF decision was revealed by their Brazilian representative in an unusual public statement on Wednesday, highlighting growing frustration in emerging nations with Fund policy to rescue debt-laden Europeans.

“Recent developments in Greece confirm some of our worst fears,” said Paulo Nogueira Batista, Brazil's executive director at the IMF, who also represents 10 small nations in Central and South America and the Caribbean.

”Implementation (of Greece's reform program) has been unsatisfactory in almost all areas; growth and debt sustainability assumptions continue to be over-optimistic“ said Batista, criticizing the IMF executive board's decision on Monday to release 1.7 billion Euros of rescue loans to Greece.

This raised to 28.4 billion Euros the total amount of funds the IMF has so far committed to Greece, an amount that Athens might default on if it gets ditched by its Euro zone partners, Batista warned.

He was pointing to a separate report published by the IMF on Wednesday, which said that if Greek reforms derail and European governments withdraw their support, then Athens' ”capacity to repay the Fund would likely be insufficient.“

”This statement is one step short of openly contemplating the possibility of a default or payment delays by Greece on its liabilities to the IMF,“ Batista said, referring to the Fund's cornerstone policy of barring countries from defaulting on it.

Nevertheless Athens received this week 4bn Euros from Euro-zone partners. The European Financial Stability Fund announced the transfer of 2.5bn Euros and the European Stability Mechanism the remaining 1.5bn Euros.

So far Greece has received 133bn Euros out of an aid package of 144.6bn from the EFSF.

The Europeans and the US, which have a majority of voting rights at the IMF executive board, have so far solidly backed Greece. US Treasury Secretary Jack Lew flew to Athens earlier this month to reiterate Washington's support.

Despite having used up almost 90% of its 240 billion Euro bailout since mid-2010, Athens is still shut out of bond markets and remains in its creditors' emergency ward.

The country's debt sustainability still depends on a pledge by Euro zone partners to provide it with further debt relief - on condition that it sticks to painful budget cuts and reforms imposed by lenders that helped cause a crippling recession.

Led by Germany, the Euro zone has pledged to consider mild debt cut relief measures for Greece next year, such as extending maturities on its rescue loans, to reduce its debt-to-GDP-ratio to 120% by 2020 from a currently projected 124%.

But Athens may need a faster, bigger debt cut, the IMF warned, to spur investor confidence and achieve the annual growth rates of about 3% which underpin its bailout plan.

”Should debt sustainability concerns prove to be weighing on investor sentiments even with the framework for debt relief now in place, European partners should consider providing relief that would entail a faster reduction in debt than currently programmed,” the report said.