The Illawarra could end up cut off from Sydney in the event of a major bushfire.
There are three main road routes linking the region to Sydney - the F6 motorway, Appin Road and Picton Road.
Each one of those cuts through extensive bushland, which places them at risk of closure should a fire start along the roadside.
"Transport for NSW works closely with NSW Police and the Rural Fire Service and follows their advice during emergencies to ensure the safety of all road users," Transport for NSW regional director Sam Knight said.
A road closed due to bushfire would not reopen immediately after the fire was out.
Road crews would be the first back in to inspect the road to ensure it is safe to be reopened - which could extend the closure time by a day, or even longer, if repairs were needed.
The South Coast train line is also at risk of being shut down by bushfires.
From Thirroul to Heathcote there is bushland along the train line.
A fire anywhere along this area would cut services to Sydney, causing major problems for commuters.
"Sydney Trains follows the advice of NSW Emergency Services on line closures during bushfires," a spokesman for Sydney Trains said.
However, a fire in one section on the South Coast line would not close the entire line.
"Services will continue to run on sections unaffected by bushfires," the spokesman said.
Again, there would be a delay between when the fire was out and when the line reopened.
"Once Emergency Services provide the all clear for lines to be re-opened, Sydney Trains has to undertake any repair work and certify the line fit for train operations before any services can resume," the spokesman said.