Toxic sludge and heavy construction noise are likely to pollute inner western Sydney as work on the Western Harbour Tunnel gets underway, leaked government documents suggest.

The “cabinet in confidence” documents reveal dredging for the $14 billion tollway project will disturb contaminated sediment resulting in toxic plumes on the harbour around White Bay.

Residents in Balmain, Rozelle and Pyrmont could also be subjected to noise pollution, Fairfax Media and the ABC reported on Monday, with a huge casting plant to be built at White Bay near the Anzac Bridge.

It will make concrete sections of the harbour tunnel which will then be shipped on barges to worksites.

Greens NSW Transport spokesperson Mehreen Faruqi says dumping thousands of tonnes of contaminated soil into White Bay and also parks across Sydney will be a disaster.

“With this plan to dump contaminated soil on to parks and playgrounds, this Liberal-National government has literally hit rock bottom for transport and environmental planning in NSW,” Ms Faruqi said in a statement on Monday.

Roads Minister Melinda Pavey declined to comment, but her office stated it would be irresponsible to publicly discuss confidential documents.

The leaked study was prepared for the NSW government before it announced the best route for the $14 billion project which is due to be completed in 2024.

The Western Harbour Tunnel will connect Rozelle in the inner west to North Sydney and the Beaches Link from Warringah to Balgowlah.

By Rachel Gray