Barcelona coach Ernesto Valverde is concerned the introduction of the video assistant referee (VAR) system may interrupt football as a spectacle.
VAR has been progressively rolled out in increasingly high-profile competitions in recent seasons, including at the World Cup finals in June and July, with mixed results.
The innovation has debuted in La Liga this season, but Valverde remains wary of its long-term impact.
"The feeling is that video assistant referees and technology are here to help us, especially for justice in the penalty area," he told the Barca website.
"But we don't know what knock-on effects it might have.
"I wouldn't want VAR to interrupt the flow of games. The great thing about football is that it's so fast, there are so few interruptions. The referees certainly need help but this shouldn't be to the detriment of the speed of the game.
"I know everyone is hanging on what happens in the area, but in the World Cup final, France scored from a free-kick that wasn't and that decided the game. So what's more important? I don't know, because I am also waiting to see how it all works out."