He made the remarks during an EU summit, where European Council President Donald Tusk reportedly clashed with European Commission chief Jean-Claude Juncker. The two men denied the reports.
"If that's your idea of Europe, you can keep it. Either give us solidarity or don't waste our time," Renzi said.
He added that if his counterparts failed to agree on the quotas, "you aren't worthy of calling yourselves Europe."
As for Juncker, he remains the driving force to back proposals for 40,000 Syrian and Eritrean asylum-seekers who have already arrived in Europe and are due to be relocated under a compulsory system.
20,000 more Syrians, who currently live in camps outside Europe, should also be resettled across EU countries.
Renzi, for his part, expressed frustration over the outcome of the summit, which obliged EU countries to take in 40,000 asylum seekers. He called relocation as a "first step," but said that "for us this is not the solution to our problems."
At least 100,000 illegal migrants have already crossed the Mediterranean, with many of them entering Malta, Italy, and Greece.