"Recent decisions like abolishing Planning Commission will cost the nation," Chavan said.
"It is dangerous to hand over financial matters to Free Economy," the Chief Minister tweeted.
Chavan's comments came after Modi tweeted that the government wants ideas from people on how the new institution which will replace Planning Commission will look.
The Prime Minister, in his Independence Day speech, had said that his government would scrap the six-decade old plan panel to set up a new think-tank that will be more federal in nature.