The sale of the Port of Newcastle has left NSW facing a potential billion-dollar liability if the state government decides to allow it to handle containers, documents commissioned during the privatisation process and made public on Thursday show.

The port is one of the world’s largest coal export terminals but has been stymied by laws that limit container movements put in place during the privatisation of Port Botany and Port Kembla under the Coalition in 2013. The Australian Competition and Consumer Commission has backed a move to allow the Port of Newcastle to handle more containers, unsuccessfully taking the matter to the Federal Court in 2018.