Transport Minister Gladys Berejiklian says the Baird government has no plans beyond what it has already announced to privatise transport services if re-elected this month.

The potential privatisation of electricity assets has emerged as the major policy difference between the Labor and the Coalition at the state election.

But at a ceremony to mark the latest milestone for the North West Rail Link, the largest public transport project undertaken by the Coalition in its first term, Ms Berejiklian said she was not looking at any proposals to privatise any further bus or rail services.

Under Ms Berejiklian's plan for the rail system, the North West Rail Link would be run by a private operator – MTR Corporation, which runs Hong Kong's train system.

The Coalition also promises to extend the North West Rail Link under Sydney Harbour and through the city to link with the existing Bankstown Line at Sydenham. This will mean that two existing rail lines – the Epping to Chatswood Line and the Bankstown Line – will eventually be run by a private operator.

"We've always said that the North West Rail Line will be operated by the private sector and that line will obviously go all the way down to Bankstown eventually and that's been in our plans and there's no further plans beyond that," Ms Berejiklian said at the Norwest Station construction site.

The Transport Minister also appeared to rule out allowing private bus operators to compete with State Transit, the government bus operator that runs services through inner Sydney.

"All I can say is, it's not in our plans," she said. "If it was in our plans we would let you know."

At Norwest, the minister was in attendance to watch the second tunnelling machine, named Florence, emerge at the planned station site after tunnelling two kilometres from Bella Vista.

"This sends a strong and clear message to the people of the north west and to the wider Sydney community that this project is going great guns," Ms Berejiklian said.

The Norwest site will be one of eight new stations on the new rail line, which is scheduled to be open for services by 2019.