Sydney's Cross City Tunnel could soon enter receivership for the second time, due to a dispute between its owners and the state government about stamp duty.

The Office of State Revenue has given the owners of the motorway until the end of the month to pay a reported $60 million bill.

The bill relates to the $700 million price the owners of the motorway - Royal Bank of Scotland, Eiser Infrastructure Partners and Leighton Holdings - paid when they bought the roadway out of receivership in 2007.

The dispute, and the possible repeat failure of the tunnel, underlines the state's chequered history with public private partnerships.

Yesterday, the government announced it would offer a $175 million lifeline to the Reliance Rail PPP to ensure the delivery of 78 Waratah trains for CityRail.

The Cross City Tunnel's outstanding stamp duty bill is worth $60 million, The Australian Financial Review reported this morning.

The paper reported that, rather than pay the bill, putting the asset into receivership would help protect its owners.

They would be paid before the Office of State Revenue, which would be listed as an unsecured creditor.

A spokeswoman for the tunnel's owners said: "The Cross City Tunnel has been a stable and successful business since changing ownership in 2007.

"The purchase in September 2007 was undertaken on the basis that no stamp duty was payable.

"The owners of the Cross City Tunnel still believe that to be the situation and are in discussions with the Office of State Revenue on the matter."