The New South Wales government recently announced it would privatise the state's largest remaining port in Newcastle for an estimated $700 million.
Coal exports are expected to double from 135 million tonnes over the next 20 years after the state government's recent expansion of the port.
It will be subject to a 99-year lease under the sell-off deal.
State treasurer Mike Baird announced the plan as part of the budget.
He said about $340 million raised from the sale would be spent on infrastructure in Newcastle, including light rail. A further $120 million from other privatised sales would also go into the project.
Labor opposition leader John Robertson said Newcastle port generates $70 million in revenue a year.
He said: “Once privatised, that revenue stream is gone forever — a stream worth much more than just $340 million.”
The Greens have accused the state government of giving false figures before the Newcastle port sell-off.
ABC Online said the Newcastle Port Corporation’s annual report shows “the organisation went from being $2 million ahead of its super payments in 2010/11, to being underfunded by more than $5.6 million the following financial year”.
New South Wales Greens MP John Kaye told the ABC: "It looks to us like they've made the asset look much more attractive than it is to bring in a bigger price.
“In the long run somebody is going to pay for this and it’ll probably be the taxpayers of New South Wales.”