Freedom of information laws may need to be extended as more organisations become involved in the delivery of public services, Scotland's data watchdog has said.

Scottish information commissioner Kevin Dunion warned on Thursday that rights to data are being lost when services are taken over by the voluntary and private sectors.

There should also be more access to information on projects such as new schools or hospitals which are funded through public-private partnerships or the private finance initiative.

"I think it is important that we review which bodies are covered by the freedom of information laws, and in addition take steps to ensure that information rights 'follow the money', where significant sums of public spending are concerned," he said.

Addressing the fifth annual freedom of information conference in Edinburgh, Dunion was also expected to highlight cases where council properties are transferred to a housing association.

"I have found contracts to build schools or hospitals can run to thousands of pages and that authorities are able to withhold these on the grounds of cost or attempt to argue that the whole contract is confidential," said the watchdog.

Dunion argues that there could be a requirement to publish contract details, while "genuinely confidential elements" could remain private.