Matteo Renzi has been sworn in as Italy's youngest prime minister at the Presidential Palace in Rome, at the swearing-in of Italy's 65th government since World War II.

Centre-left Mr Renzi promised yesterday to start work on reforms immediately, after he named a new cabinet and formally accepted the mandate to form an administration, he said would stay in place until 2018.

At 39, he will be Italy's youngest prime minister and heads a cabinet made up mainly of ministers in their 40s and 50s, half of them women, continuing the rejuvenation of the elderly caste which used to run Italian politics.

He confirmed that OECD (Organisation for Economic Co-operation and Development) Chief Economist Pier Carlo Padoan, who was forced to hurry back from Australia, would take over at the economy ministry where he will play a central role in Mr Renzi's bid to revitalise Italy's stagnant economy.

But there were few other big names in a 16-member cabinet, dominated by relatively low-profile politicians with a sprinkling of non-political officials.

With a cabinet boasting no star names, the success or failure of the government will be down to the ambitious Mr Renzi, who forced out party rival Enrico Letta last week, following a stream of criticism over the slow pace of economic reforms.