The incident has caused tailbacks towards the A191 Holystone junction.
Tunnel operator TT2 said recovery teams are working to move the vehicle and traffic is ‘still flowing’.
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A spokesperson said: “We have a vehicle who has struck the Metro Bridge on approach to the Southbound tunnel. Recovery is en route. Traffic is still flowing. Apologies for any delays caused. We will keep you updated on any further movements.”
Northumbria Police has recommended motorists reconsider their travel plans while the disruption continues.
A spokesman for the force said: “Shortly after 8.20am, it was reported that a lorry had collided with the metro bridge just before the Tyne Tunnel, southbound.
“No injuries have been reported and emergency services and partners remain at the scene.
“Traffic is currently moving slowly through the area and commuters are advised to seek an alternative route if possible.”