The sale of a significant portion of NSW's electricity network could be used to pay for ambitious infrastructure plans proposed by the state government.

NSW Premier Mike Baird said the $20 billion sale of a hefty portion the state’s electricity network would permit the funding of a swathe of ambitious infrastructure projects, including a second rail crossing for Sydney Harbour and three new underground metro stations in the CBD.

The state cabinet has given its support to a proposal for the 99-year lease of 49 per cent of the NSW electricity network, with a scoping study set to decide how much of Ausgrid, Endeavour Energy and Transgrid will be made available for sale.

Those parts of the electricity network responsible for supplying power to rural and regional areas will be exempt from the leasing, however, due to the Nationals’ concerns about potential employment impacts.

In order to forestall any concerns about private owners ramping up prices, the plan proposes a discount of one per cent off forecast regulated prices until 2019.

The $20 billion raised by the sale of nearly half of the power network will be put towards a diverse set of infrastructure plans, including $6 billion for road and water projects in regional areas.

Sydney will also receive a new rapid transit rail under the plan, which will include another crossing for its iconic harbour, while the north-west rail link will be extended to Bankstown via the CBD, which will enjoy three new underground metro stations.

The Westconnex motorway will also undergo extension towards both the north and south.

Liberal MPs reportedly did not take much convincing to give their endorsement to the new plan. The Nationals felt greater trepidation, however, meeting for over four hours before agreeing to provide their support.

 Baird has hailed the decision as making for a “historic” day in the state.

Opposition leader John Robertson said that the plan would lead to the loss of $1 billion a year on average in government funds derived from network business dividends, and that the new infrastructure promises would do little to sway voters in the state.

“Frankly for Mike Baird to think he can pork-barrel his way into selling these assets by offering all of these wonderful things, I think he underestimates the people of NSW,” Robertson said.