Premier Mike Baird's bill to lease 49 per cent of the state's electricity network to private leaseholders for 99 years, narrowly passed in the NSW Parliament's Legislative Council late on Wednesday night.

Liberal MPs cheered, while one disgruntled MP yelled "bugger" as the bill passed 19-17, with the vote hinging on the support of Christian Democratic Party leader Reverend Fred Nile.

Labor, the Greens and the Shooters and Fishers Party voted against the bill.

"What last night's vote, and again this morning's vote [on amendments], confirms is that we will get on with building the Albion Park Rail bypass, which I committed to at the last election," Kiama MP, and parliamentary secretary for the Illawarra and South Coast, Gareth Ward said.

"In line with our commitment, work will start in 2018."

Shellharbour MP Anna Watson said questions around the bypass's construction remained unanswered.

"We still don't know what the sale price of the electricity network will be," Ms Watson said.

"If the government is unable to raise the expected $20 billion from the sale, this will place the Albion Park Rail bypass project at risk."

Mr Ward said: "The only people who have gotten in the way of this project are Labor.

"They try and claim that they're for it but why, if they are, have they never actually supported it?" he said. "Obviously we've got to make sure that we get the revenue as expected and now that the bills have passed through, we've got to go through the process of leasing the assets in order to have the cash and that's what we'll do."

Illawarra Business Chamber chief executive Debra Murphy commended the government for "persevering with this important reform".

"The passing of legislation to allow the partial lease of the electricity network provides a once-in-a-generation boost for infrastructure investment across our state, with the construction of new roads, railways, hospitals and schools set to boost economic growth in the Illawarra region," Ms Murphy said.

Wollongong MP Noreen Hay was cautioned over ‘‘unparliamentary language’’ directed at NSW Premier Mike Baird during debate over the privatisation of the state’s electricity poles and wires on Thursday. 

Ms Hay was pulled into line by the Speaker, South Coast MP Shelley Hancock, during question time in State Parliament on what Mr Baird said was a ‘‘significant day for NSW’’.

‘‘One that this government is very proud to be a part of because we have a new era in NSW,’’ Mr Baird said.

‘‘A period where we’re going to step change our infrastructure, we’re going to march forward and we’re going to deliver projects that when you [Labor] were in government you spoke about, you thought about, you dithered on; well, we’re going to deliver them.’’ 

Mr Baird later mentioned  that his ‘‘good friends from the Illawarra’’ were against the Albion Park Rail bypass – ‘‘$550 million; they came in here and they said, ‘No, we don’t want it’ ... well, the member for Kiama [Gareth Ward] and this government is one that wants to deliver it’’.

Ms Hay interjected twice to ask, ‘‘Where’s the lifts for Unanderra?’’, while an inaudible comment  that followed appeared to be aimed directly at Mr Baird.

‘‘Member for Wollongong, that’s a personal reflection against the Premier; unparliamentary language, so not like you,’’ Mrs Hancock said.