FIFA's head of refereeing Massimo Busacca praised the implementation of video assistant referees (VAR) at the Confederations Cup but conceded the much-discussed system must be reformed and improved.

The use of VAR has come under the spotlight on a number of occasions during the tournament in Russia, most recently during Germany's 3-1 win over Cameroon in Sochi on Sunday when referee Wilmar Roldan sent off the wrong player before having his mistake corrected.

FIFA is not yet committed to using VAR at the World Cup in Russia next year and will undertake a review of its operation at the end of the Confederations Cup.

Busacca, a Swiss former referee who took charge of the 2009 Champions League final and officiated at the 2006 and 2010 World Cups, told a news conference in St Petersburg on Monday that individual member federations must allow refereeing teams to work with the system in order to iron out kinks, given FIFA has a limited amount of tournaments at its disposal to road test the technology.

"We feel VAR was very good. We are always positive," he said. "We had good results but maybe aspects should be improved.

"It is important to mention that no clear mistake was missed [at the Confederations Cup] and this is what we're looking for, clear errors. This is recognising the protocol.

"In 12 games, we had 29 major incidents decided correctly by the officials and confirmed by VAR; seven decisions reviewed by VAR and six game-changing decisions corrected. Four of those were offside.

"After this competition, we can work for the future and we have to. Implementation needs time. Now many important member associations will start officially in a few months

"It will be incredible to see how it can be implemented places like Italy and Germany. But in FIFA we have just a few competitions in a year. We have the Club World Cup before the World Cup and that's it.

"Every referee team in every country that is supplying officials to the World Cup need to be working with VAR every day.

"In five days we did the VAR training for this competition. To implement more, to be at the level we need, we need time."

Addressing the confusion wrought at Fisht Stadium, when it was ruled Cameroon defender Ernest Mabouka should be punished with a red and not yellow card for a high lunge on Emre Can, only for midfielder Sebastien Siani to initially be given his marching orders, Busacca admitted the VAR process had taken far too long.

However, he sympathised with Roldan over the case of mistaken identity – something he endured in his own career – and praised the correct decision being reached, albeit in an unseemly manner.

"I have to agree with you it was too long but in the end the correct player went outside," he added.

"I can tell you it happened to me also in my career. In the end the players helped me to find the right [shirt] number, thank God.

"Imagine now, having this referee - without VAR  - giving the wrong player a yellow card and missing a clear red card.

"Now [the delay] does not look good but in the end the honesty of the game was there."