The current Olympic title holders have held the World League title since 2013, while Italy and Croatia have won silver and bronze medals, respectively, this year.

Croatia won the World Championships tournament, ahead of Hungary and Serbia, in Budapest earlier this year.

Serbian coach Dejan Savic has called up all the players who have won a bronze medal at the World Championship,  except for the injured Stefan Mitrovic.

In his place he has named Strahinja Rasovic.

“We want to play with the best squad available at the moment because we still don’t know where the Super Final tournament is going to be held so there is a possibility that the best second placed team also qualifies for it," said Savic.

"We know the Romanian team very well. 

"The most important thing for us is to gather up again for the first time since August and to train and play well."

The competition takes place in a number of locations with nine of the very best nations going head-to-head.

Group A consists of Montenegro, Romania and Serbia. 

Group B has Croatia, Germany and Russia and Group C is made up of Hungary and The Netherlands.

Romania travel to Serbia tomorrow to play them in Zrenjainin, while Croatia will host Russia in Zadar and Spain welcome the Dutch in Malaga.

On December 12 the action continues with Montenegro facing Serbia, Germany against Russia and Hungary versus The Netherlands.

January 16 next sees Montenegro play Romania, Croatia against Germany and Hungary playing Spain.

February 13 sees Romania in action against Serbia, Croatia against Russia and Spain versus The Netherlands.

On February 20, it will be the turn of Montenegro versus Serbia, Germany versus Russia and Hungary versus The Netherlands, while April 10 sees Montenegro play Romania, Croatia playing Germany and Hungary playing Spain.

After the conclusion of these six rounds, the four best teams will be qualified for the Super Final, to be held from June 18 to 23 next, and they will then be joined by four other teams selected from Intercontinental Tournaments.

The locations of future matches have yet to be confirmed.

Croatian coach Ivica Tucak said he expects a tough baptism for many of the less experienced players in his squad.

“One of our main goals in the World League is to test as many players as we can and also to rest those who led the team in previous years," he said.

"The most important competition in this year is the European Championship. 

"So that’s why we need to test a lot of players. 

"I hope that we will compete for the gold medal at Euro."

Last season the Spanish water polo team did not play in the World League, while The Netherlands were eliminated in the preliminary phase.