SYDNEY, AAP – The NSW infrastructure minister denies the cost of three Sydney road projects have blown out by about $1.4 billion in the last financial year.

Rob Stokes said the government’s M6, WestConnex and Sydney Gateway projects all remained within their budgeted figures for 2021/22, after a Transport for NSW spokesman told Nine Newspapers the projects had increased by $1.4 billion.

Questioned at a budget estimates committee hearing on whether the M6’s costs had risen by $400 million, Mr Stokes said the project’s budgeted figure had not changed, according to his advice.

“My understanding is that the budget for the project, which I think was $3.115 billion, continues to be the budget for the project,” Mr Stokes told the hearing on Monday.

Labor MLC John Graham asked Mr Stokes why a spokesman from Transport for NSW had claimed the three projects were over budget.

“I’m being honest, and I’m pointing you to the budget papers,” Mr Stokes said.

“The $3.115 billion figure is in the budget papers.”

Shadow treasurer Daniel Mookhey asked the cost of the Sydney Gateway, to which Mr Stokes responded: “I think you’ll find it’s $2.1 billion”.

Recent publications on work sites indicated the updated cost to be $2.5 billion, he said.

The Transport for NSW spokesman’s claims added up to a doubling of the project’s original costing, and construction was about $775 million per kilometre, while WestConnex cost $509 million per kilometre.

The Transport for NSW spokesman had attributed the cost blowout to the rising price of labour and the COVID-19 pandemic.

Mr Stokes did not agree.

The 2020-2021 Report on State Finances, tabled in parliament last month, found the budget for construction of the Sydney Gateway, the M6 Stage 1 and the WestConnex Rozelle Interchange had blown out by $1.4 billion.

The report detailed costs for Transport for NSW for the 2020/21 financial year were $9.68 billion, up from $8.26 billion in 2019/20, and said the rise was “driven by (commitments to) M6 Stage 1, WCX Rozelle Interchange, and Sydney Gateway”.

Opposition Leader Chris Minns said informing the public about the cost of a project was the “minimum obligation of the minister responsible”.

“One of the obviously distressing things about this situation is not just that the information leads up huge cost blow out … but that the minister today when he was questioned about it refused to provide any information at all,” Mr Minns said.

“This is not the NSW government’s money, it’s the people of NSW’s money.

“You should be up front and honest when there’s a cost blowout associated with this sort of infrastructure.”

The Sydney Gateway project will connect St Peters and Sydney’s domestic and international airport.

The Rozelle interchange is an underground motorway with a link to Victoria Road, the Iron Cove Bridge, Anzac Bridge, and Western Harbour Tunnel.

The M6 Stage 1 is a four-kilometre tunnel connecting the M5 at Arncliffe to President Ave at Kogarah in south Sydney. The project is the first of three stages designed to provide better access to south Sydney.