Cerar, who is the sole contender for party president, has revealed little about the platform or his associates, however, he has indicated the group will seek to overcome the left-right ideological divide.

Except for the president, the congress will also elect an executive committee and party council, while Cerar does not expect vice-presidents to be elected yet, as new members are still joining.

Cerar says his party will be independent and not part of any of the existing blocs.

Agreeing that cooperation will be inevitable after the election, Cerar has been reluctant to talk about pre-election alliances yet because the party bodies elected today will decide yet whether the party will head to the polls on its own.

Cerar's party is the latest in a series of new parties mushrooming left of the centre. Unlike some other emerging leaders, Cerar was not in attendance as outgoing Prime Minister Alenka Bratušek established her alliance on Saturday.

A public opinion poll conducted along with the exit polls in Sunday's election to the European Parliament suggested Cerar's party could win 12 of the 90 seats at the National Assembly in the snap general election to become the second strongest faction after Janez Janša's Democratic Party (SDS).