Investment guru Nouriel Roubini criticizes the euro zone-International Monetary Fund rescue package for Greece for not involving the IMF enough and providing money only after an emergency.

“The idea that you’ll provide money only in an emergency, I’m not sure it makes sense,” Roubini says.

It’s better to provide money upfront, because even a country that makes fiscal adjustment might have debt-refinancing problems, he says.

“One of the reasons why the ECB (European Central Bank) and Europe were against excessive IMF involvement is that they were concerned IMF conditionality won’t be as strong as the EU (European Union),” Roubini told Bloomberg.

“My worry is that the EU is imposing even more fiscal austerity than is necessary, especially the Germans, who are hell bent in extracting not two or three, but five or more pounds of flesh from Greece.”

And why should the IMF have a greater role?

“It has 50 years of experience of realizing why you need medium-term fiscal sustainability,” Roubini said.

“In the short run if you raise taxes too much and cut spending too much, the risk becomes even worse. An IMF solution would have been cleaner.”

Investment legend Jim Rogers thinks both the IMF and euro zone went too far.

"The Greeks have never lived within their means, and I suspect this time they won't either, until they're forced to by either bankruptcy or by someone just refusing to give them loans," he told CNBC.