It is been revealed that Sydney's Lane Cove tunnel is up for sale.

The tunnel's owner, Connector Motorways Consortium is unable to meet debt repayments, because traffic volumes have not met original forecasts of 100,000 cars a day.

A spokesman for Connector Motorways says all the equity holders, including Leighton Holdings have written off their stakes.

The state opposition's roads spokesman Andrew Stoner says the Government should shoulder some of the blame for the tunnel's troubles.

"They were the ones who commissioned this project in the first place," he said.

"They were the ones who provided the dodgy traffic volume estimates on which the finances were based.

"They were also the ones who ticked off on a toll regime which, in the economic circumstances, was too steep for many motorists."

But the Transport Minister David Campbell says the data was not provided by the State Government.

"The Government didn't twist anybody's arm, the Government didn't legislate to force anybody to make an investment," he said.

"The private sector made an investment on their own calculation, and in the future, PPPs will be determined in a similar way. "

The Lane Cove Tunnel is a 3.6 kilometre motorway under Epping Road that links the M2 Motorway at North Ryde with the Gore Hill Freeway at Artarmon.

It opened in early 2007 and cost $1 billion to build.