Italy's newly elected Parliament was heading toward political gridlock as it meets for the first time after inconclusive elections gave no party a clear victory.

Investors will keep a close eye on the inaugural session today, when both chambers will vote for leaders. Only then can Italy's president open talks on forming a government, expected next week.

Even before Parliament opened, the parties were locked in a stalemate.

Centre-left leader Pier Luigi Bersani, whose coalition came first in February 24-25 elections, said his MPs will cast blank ballots after failing to persuade comic-turned-political leader Beppe Grillo's 5 Star Movement, which finished third, to co-operate on a leadership strategy.

The anti-establishment movement will only vote for its own candidates - which cannot guarantee a winner.

Voting was expected to continue Saturday.