Rome: Italy's Constitutional Court on Wednesday ruled that most of a contested electoral law was valid in a verdict that could lead to early elections this year.

"The electoral law can be immediately applied," the court said in a statement.

The court ruling upheld the law's provision that any party which took at least 40 percent of the vote should win an automatic parliamentary majority, but said that national elections could not be held over two rounds. 

The law had first been drawn up to apply only to the lower house of parliament as Italy's upper house Senate was due to be abolished as an elected body under constitutional reforms that were resoundingly rejected by voters in a referendum last month.

Italian Premier Matteo Renzi resigned after his crushing referendum defeat but remains secretary of the ruling centre-left Democratic Party and has said he wants snap elections.

President Sergio Mattarella held off calling early elections until after the Constitutional Court ruling.

A national vote is not slated until early 2018 but opposition parties including the Five-Star Movement - Italy's largest opposition group - and the anti-immigrant Northern League are also calling for early polls.-Agency