Sydney's Cross City Tunnel is attracting only about half the number of cars its first owners said would travel through it eight years ago.
Weak traffic numbers mean the motorway continues to struggle financially, and is facing receivership for the second time since it opened in 2005.
Lenders to the consortium that owns the motorway are understood to be considering putting the tunnel into receivership, due to concerns over a disputed $60 million stamp duty bill, and the lower traffic numbers.
The owners of the motorway - Leighton Holdings, the Royal Bank of Scotland and EISER Infrastructure Partners - do not disclose the number of vehicles that travel through the controversial toll road every day.
But the last time the NSW government revealed the figure, in 2009, just 35,400 cars per day on average used the motorway.
In contrast, patronage forecasts by the tunnel's first owners predicted 70,000 cars would be using the tunnel daily in 2005 and more than 90,000 a day by 2013.
The tunnel opened in 2005 at a cost of $680 million and went into receivership in 2006.
Annual reports issued by its current owners, who bought it out of receivership in 2007, show toll revenue growth has increased only at the rate of inflation since 2009.
A spokesman for the motorway said the Cross City Motorway company was "still actively renegotiating to refinance the debt", referring to a $79 million loan it had wanted to renegotiate this month.
But those negotiations have been thrown into doubt by a $60 million stamp duty bill. The motorway successfully challenged this bill in the Supreme Court but the Office of State Revenue has since filed a notice of intent to appeal, placing its future ownership in the hands of main lender RBS.