HIGHLY sensitive documents that may reveal the state government's plans for the privatisation of some Sydney Water assets and services are being suppressed because of claims their release is not in the public interest.

The NSW opposition had applied under freedom of information laws for details of the government's plans for the ownership of wastewater treatment plants.

Opposition spokesman Walter Secord ... lodged a freedom of information request asking the government for details of any proposals to outsource, franchise or sell Sydney Water's treatment plants. Credit:Jacky Ghossein

Now, the government has confirmed it is investigating options raised by the NSW Commission of Audit Report, released in August.

The report recommends increased outsourcing where the private sector and non-government organisations can deliver ''better services at lower cost and with greater innovation''.