Italy’s Five Star Movement, which forms one half of the governing coalition, suffered a fresh humiliation on Monday after winning an estimated 11 per cent of votes in Sardinia's regional election.

If confirmed once counting is completed, it would mark a precipitous decline from the 42 per cent of votes that the party won on the island during Italy’s general election less than a year ago.

The dismal performance could inflame tensions with the hard-Right League, which has emerged as the more powerful of the two parties since they were sworn into government last summer.

The League is led by Matteo Salvini, who has eclipsed his fellow deputy prime minister, Luigi di Maio of Five Star, with a crackdown on migrant arrivals in the Mediterranean and the savvy use of social media platforms to publicise his policies.

Mr Salvini has vowed to lead a populist surge at the European Parliament elections in May, setting the stage for a showdown with the EU establishment.

The two parties are at odds over a wide range of issues, from the treatment of asylum seekers to whether to proceed with a rail link beneath the Alps that would link Turin with Lyons as part of a larger pan-European transport network.