The heavily indebted nation's borrowing costs have jumped due to investor fears over Rome's plan to boost deficit spending. The government wants to fund costly electoral promises such as a lower retirement age and a basic income for the poor.

Italy sold a new three-year bond at a yield of 2.51 percent, the highest since September 2013.

Overall, including other issues maturing over seven, 15 and 30 years, Italy's treasury raised 6.5 billion euros ($7.5 billion), the maximum it had set itself ahead of the auction.