The large crack appeared on two inbound lanes of the bridge, and authorities immediately shut down the road to investigate.

The bridge has now been re-opened but it will be closed again later tonight – and drivers must adhere to a reduced speed limit.

Acting chief executive officer Peter Todd said the crack might be a result of Melbourne’s recent heatwave.

He explained: “The bridge is made of steel, and it would have been expanded significantly, then in this cooler weather, it would have contracted.”

He added: “It may well have been the movement of the bridge during this hot weather that has caused the problem. It’s a bit like getting a tear in your carpet, yes, it’s annoying and you’ve got to fix the tear in your carpet, but the floor is sound.”

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