A truck fire has affected traffic in both directions in Hume Street between the Hume Highway and Ducks Lane.
The road is closed in both directions, according to the Transport Management Centre.
A Fire and Rescue NSW spokesman said the truck was carrying logs that were "fully involved in fire".
A second FRNSW spokesman said it was understood firefighters intended to evacuate Bunnings due to the smoke plume.
"There's no injuries and no life risk," the spokesman said.
Motorists should instead use Sydney Road to access Goulburn.
Transport NSW crews are also working at the scene.
Motorists are advised to avoid the area, use an alternative route and exercise caution.