5-Star new leader Luigi Di Maio talks during a gathering in Rimini, Italy, Sept 23, 2017. [Photo/Agencies]

RIMINI, Italy - The new leader of Italy's anti-establishment 5-Star movement says it is not a populist party and will make cutting waste and reducing debt its priority.

5-Star, which leads most opinion polls ahead of national elections due early next year, has been trying to shed its maverick, populist image and reassure foreign capitals that it can be trusted with power.

Luigi Di Maio, the 31-year-old lawmaker picked on Saturday to lead the movement, told Reuters on Sunday that 5-Star stood for "post ideological" common sense, and was opposed to right-wing and left-wing extremism.

"I reject populism as a label for 5-Star," he said in an interview on the sidelines of the party's annual gathering in Rimini, on the Adriatic coast.

5-Star, founded by comedian Beppe Grillo nine years ago as a protest movement, bases its appeal mainly on opposition to corruption and vested interests.

Boyish-looking and usually immaculately turned out in suit and tie, Di Maio presents a more moderate image than Grillo, who is famous for raucous tirades against the ruling elite.

He had been groomed for the leadership by Grillo, who is 69 and now plans to withdraw gradually from his figurehead role.

Di Maio said many of the party's proposals, such as a public bank to fund investments, had been adopted with success by mainstream parties in Northern Europe which he wanted to emulate.