Mike Baird is refusing to detail how he plans to turn $13 billion from the sale of electricity assets into $20 billion for new infrastructure, in response to opposition claims that this process would require no spending of the proceeds for a decade.

The Premier has outlined $20 billion in projects he wants to fund from the privatisation if he wins next year's election. All but one, the Western Harbour Tunnel, are due for completion within 10 years.

Privatisation to fund $20 billion in projects: Premier Mike Baird. Credit:Brett Hemmings

But Mr Baird has also said he expects to earn $5 billion in interest from the sale proceeds during that time – a feat Labor says would require the money to be invested for the entire period, with none spent on infrastructure.

Announcing the proposed sale in June, Mr Baird said the "conservative" expectation was that the lease would deliver $13 billion.