Italy's far-right League has triumphed over its Five Star Movement coalition partner in a regional vote seen as a test of strength ahead of crunch European elections, results showed Monday.

The vote in the Abruzzo region laid bare the difficulties for the Five Star Movement (M5S), which was the country's leading party at last year's general election but has seen its popularity recede since taking power in an uneasy coalition with the League.

The anti-immigration League, led by hardline Interior Minister Matteo Salvini, won 28 percent in Abruzzo's local elections on Sunday, compared with 19 percent for M5S, the interior ministry said.

A League-led alliance that included its old centre-right ally, former prime minister Silvio Berlusconi's Forza Italia party, took just over 48 percent of the vote, handing the post of Abruzzo regional president to the bloc's candidate Marco Marsilio.

"Thank you Abruzzo! Thank you Italy," said Salvini.

Five Star candidate Sara Marcozzi said it was "not a defeat for M5S but for democracy".

The regional vote is seen as a bellwether ahead of the European elections in May.

Success in the European polls would strengthen the League's hand further, with expectations that it could spur Salvini into pushing for fresh elections in a bid to ditch its coalition partner.

While the M5S won 33 percent in the general election last year, far outstripping the League's 17 percent, it has since watched the stellar rise of Salvini's party, thanks in part to its hardline stance on immigration.

The League is now favoured by 34 percent of voters, according to an Ipsos poll on Monday.

Both M5S head Luigi Di Maio and Salvini had campaigned heavily in the mountainous Abruzzo region ahead of the weekend vote.

The center-left, which has struggled to put up a united front against the populists, had a strong showing with 31 percent.