Delays in the Folkestone area mean thousands of Welsh faces are facing long delays and the possibility of missing the start of the game, which is scheduled to start at 20:00 BST.
Supporters arriving at Folkestone have been told they face an hour-long wait to board a train as the international service continues to struggle to recover after a train broke down overnight.
Three additional trains have been added to the service to help alleviate the problem and Uefa have confirmed they are not yet considering revising the game's start time.
An official Uefa statement read: "Uefa is aware of the current delays in the Eurotunnel and has gathered further information from the Welsh FA, local authorities and the tunnel operator.
"It appears that the vast majority of fans with tickets will arrive on time at the stadium in Lille.
"The match is therefore scheduled to go ahead as planned with a kick-off time of 21:00 CET (20:00 BST).
"Uefa will continue to closely monitor any developments around this situation."
Wales have not featured in a quarter-final at a major international tournament since 1958 and manager Chris Coleman has described the clash as one of the biggest games the nation has been involved in.
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