FIFA President Gianni Infantino signaled that he is in favour of introducing video assistant referees (VAR) at next year’s World Cup following its success at the Confederations Cup, although he conceded the system needs to be improved.

“Nothing is standing in the way of using VAR (at the World Cup), as far as I’m concerned,” Infantino told a news conference in the Russian city of St Petersburg on the eve of the Confederations Cup final.

“So far it has been successful. We are learning, we are improving, we are continuing the tests.”

VAR involves two video assistant referees watching the on-pitch action remotely and then drawing the match referee’s attention to officiating mistakes.

FIFA said the system corrected six game-changing decisions during the Confederations Cup.

“Without the VARs, we would have had a different tournament,” Infantino said. “And a tournament which would have been a little less fair.”

But Infantino, who said that the system had been tested so far in 74 matches, added that certain aspects needed to be refined.

“We need to work still on some of the details, on the communication and the speed of the decisions being taken,” he said.

The time needed to make decisions has been criticized. There has also been debate about which circumstances it should be used for as some close calls are decided without consulting the VARs.

The use of the system has caused controversy at times, such as during Germany’s 3-1 group stage win against Cameroon when referee Wilmar Roldan needed two reviews of an incident to send off the correct Cameroon player.

Chile were denied a legitimate-looking goal after video review in their 2-0 win against Cameroon on June 18, and it was again used at the end of the same match to overturn a linesman’s offside call and award Chile a goal.

Former World Cup final referee Pierluigi Collina, the chairman of FIFA’s referees committee, said on Saturday that the system was a “very positive tool” to help referees make the right calls and took pressure off them.

“We are in a sort of work in progress,” Collina told reporters. “We see the very positive result we had but we are aware that we can improve. This is normal.”

Soccer’s law-making body IFAB is expected to decide next March whether to allow video assistant referees to become part of the game on a permanent basis.

Chile face World Cup holders Germany in Sunday’s Confederations Cup final.