Excitement over trillion-dollar Greek rescue package sours slightly

Enthusiasm over the euro zone's mammoth $1-trillion rescue package for Greece today turned to doubts whether its weakest economies can meet their end of the bargain and deliver drastic debt cuts, driving the euro and stocks lower.

The emergency plan - the biggest since G20 leaders threw money at the global economy following the collapse of Lehman Brothers in 2008 - impressed markets with its sheer size and sparked a spectacular rally in world stocks and the euro.

Yet, financial markets turned cautious when they reopened for business in Asia this morning, with investors concerned that the plan was not a long-term solution to problems plaguing the 11-year old single currency area.

In a sobering note, the International Monetary Fund said that even though Greece's public debt was sustainable over the medium term, the nation whose debt woes spurred the unprecedented euro zone action faced plenty of risks.

Moody's credit ratings agency also warned it might downgrade Portugal's debt rating and further cut Greece's to junk status, noting the contagion effect of Greece's crisis on other euro zone members.

"Contagion has spread from Greece - historically a weaker credit in the context of the euro zone - to sovereigns with stronger credit metrics like Portugal, Ireland and Spain," Moody's said.