“Austerity policies are clouding the horizon. They have turned the future into a threat. They have given fear a push,” Renzi wrote in an article published on Sunday by financial daily Il Sole 24 Ore.
Renzi is due in Berlin on Monday to discuss how the EU reacts to Brexit with German Chancellor Angela Merkel and French President Francois Hollande.
Italy is a long-standing critic of EU economic policy as overly focused on fiscal rigour at the expense of fostering jobs and growth.
And Renzi said his demand for greater flexibility on the bloc's budget rules had been made more urgent because of the shockwaves from the British vote.
“Let's try to wake up now,” Renzi wrote. “To wake up better than we did on Friday morning.
“Without growth, there are no jobs. Without investment, there is no tomorrow. Without (budgetary) flexibility, there is no community.”
Arguing that the Brexit vote was prompted by collapse of manufacturing industry in parts of England, Renzi added: “Europe is not finished. It only needs to be liberated from resentment, bureacracy and myopia.”
As well as jobs and growth, Italy's priorities for the post-Brexit EU include an acceleration of moves towards a Eurozone banking union, which Germany is opposed to.
Rome is also pushing its plan to end the migrant crisis by paying African countries to take back some of those arriving in Europe and restrict others from leaving.