Matteo Renzi, the former prime minister, had his address and telephone numbers published

Personal information about some of Italy’s leading political figures has been published online after hackers broke into the databases of two of the country’s largest parties weeks before the general election.

The hackers, who identified themselves on Twitter as AnonPlus, published the names and addresses of 2,653 members of the Democratic Party in Florence, including details for Matteo Renzi, the former prime minister.

The breach included his address and telephone numbers, although his aides said the numbers, which have now been removed from Twitter, were out of date.

Another hacker collective, Rogue_0, published personal data belonging to Davide Casaleggio, the man responsible for the online voting system used by the populist Five Star Movement, which advocates direct democracy.

In Mr Casaleggio’s case the security breach