Gary Neville is concerned that VAR officials at the World Cup do not have the technical skill to make the right decisions quickly.
The Sky Sports pundit was speaking after Argentina's 1-1 draw with Iceland when substitute Cristian Pavon was not awarded a 77th-minute penalty after falling under a challenge from Birkir Saevarsson.
Replays indicated the Iceland defender had committed a foul, but Polish referee Szymon Marciniak was not convinced and play was restarted before the VAR team in Moscow could intervene.
And Neville believes it is proving too hard for the referees to find the right camera angle and make a decision within a few seconds.
"To me, there is a capability issue here over what we're asking the referees in that VAR truck to do," he told ITV.
"There are 40 camera angles and you might say there are only 10 camera angles you need to look at, but you're asking the VAR official, with two mates alongside him, to make a decision in 10 or 15 seconds.
"He's got one television screen split into nine or 10 multiple screens like a Rubik's Cube. He has got pressure on him to try and pick the right angle and look at them quickly.
"Co-commentators get it wrong sometimes, commentators get it wrong and analysts get it wrong.
"They are being asked to make decisions in real, quick speed. There is a capability issue here about whether they can actually do it in such a quick time and get the right angles and views. That's my worry.
"I don't know what's going on in those trucks, but that's the thing they need to be transparent about and show us.
"I'm not sure they will be able to select the angles quickly enough to get the decision back to the referee before the game has been restarted."