Wales coach Gareth Jenkins was furious with the officials after being denied a chance to secure a draw with Italy.
Gareth Thomas leads the Wales protests in Rome
James Hook kicked for touch after the referee said there was 10 seconds left, but the final whistle then blew before Wales could take the line-out.
"The instruction from the ref was clear that we had time to win the game," said Jenkins after the 23-20 defeat.
"He then had a message in his ear to say time was over. If we had known that, we would have gone for the draw."
Jenkins added: "It's more than frustrating and realistically it's a bad call.
"A mistake has been made here and we could have come away with a result if we had been clear on the situation.
"We're not only angry but very disappointed. It was a game full of drama.
"There was a lot of opportunity there for us, and with different decisions we could have come away with a couple more tries.
We lacked composure and we're still not making the right decisions at the right time
Wales coach Gareth Jenkins
"We've ended up losing the game under controversy and we don't want to end big occasions in that way.
"These things happen. It's too late, we can't change the event but it is frustrating."
Winger Shane Williams, Wales' first try-scorer at the Stadio Flaminio, insisted that White had told the players there was time for a final play.
He said: "We asked how long we had left and he said there was about 10 seconds.
"We asked if we could kick to touch and he said 'yes, carry on'. You could see by our faces we were gutted, but that's the way rugby goes.
"You can't complain about it and Italy played well."
Referee White left the stadium without commenting on the controversy.
Wales led 16-20 going into the final five minutes, but Mauro Bergamasco's converted try gave Italy victory.
The defeat leaves Wales bottom of the Six Nations table without a win, and Jenkins said his players continue to be their own worst enemy.
"We lacked composure and we're still not making the right decisions at the right time. It's costing us dearly," he said.
"We did try to play rugby and opened Italy up on occasions.
"But some indiscipline let Italy back into it and allowed them to take the win from us."