Traffic on Sydney's Eastern Distributor has been thrown into chaos by a truck that hit the tunnel's sprinkler system.

The tunnel was damaged early this morning and it took crews until shortly before 3pm (AEDT) to remove it and fully re-open the distributor to traffic.

By 11am a queue of more than six kilometres had formed.

Drivers were being diverted to the Bondi-Randwick exit of the tunnel for most of the day.

Rebecca Walsh from the Transport Management Centre said while the truck was still in the tunnel that it was a difficult operation.

Crews are working to clear the Eastern Distributor before the afternoon traffic begins to build. ( ABC News )

"They have to actually deflate the tyres is my understanding and there's issues with the hydraulics of the truck.

"They do need to get a crane in and they do have a heavy vehicle tow there to remove it."