Italy became the first heavyweight nation to cast votes for the EU's next parliament on Saturday, in a test of far-right leader Giorgia Meloni's strength at home.

Most of the European Union's 27 member countries, including France and Germany, will vote on Sunday, the final day, with projected overall results due late that evening.

The first polling stations have already opened in the French Pacific territory of New Caledonia, the site of deadly rioting this month.

The two-day ballot in Italy, the EU's third-largest economy with 76 of 720 seats in the new parliament, could have significant consequences.

After casting her vote in Rome, Meloni told reporters that the EU contest "will shape the next five years".

Polls suggest Meloni's Brothers of Italy party could win with 27 percent of the vote -- more than quadrupling its score from 2019 -- amid a broader surge of far-right groups across the bloc.