Major public-sector employers could follow the lead of the police and use covert surveillance to check up on staff believed to be exploiting sick pay.
With spiralling ill-health and early retirement costing the public sector dear, experts say spying on staff could become more widespread.
David Crichton-Miller, a consultant with the Risk Advisory Group, said any move towards covert surveillance by police forces would create pressure on other public-sector employers.
He said, "I am absolutely sure that there is a general trend toward being more scrupulous on this type of point. Anything that is reasonably widely held up would tend to put on the pressure in that direction because it is public money that is being lost."
The news come after the Association of Chief Police Officers revealed it may recommend surveillance to forces in guidance to be issued later this year. If implemented, other employers could follow suit.
A spokesman for the association said, "It is being considered at the moment. If we had reason to suspect that an officer was lying, then we would take a very serious view. Certainly surveillance would be an option.
"We would not need to contract it out to private investigators as covert surveillance is one of the options that is available within forces."
Employment law consultant David Marshland, of William M Mercer, said he does not expect the practice to become widespread - even if it is adopted by chief constables.
But he added that an increase in the number of employers using it would be inevitable.
"I think in time if you get an impression that other organisations are doing something like this your own likelihood of doing it becomes greater."
Mike Lewis, assistant chief constable of South Wales Police, said he would be prepared to monitor officers suspected of malingering.
He said, "We have adopted a robust approach to sickness. While the overwhelming majority of people taking sick leave are genuinely ill, this management is designed to weed out the small number abusing the system."
By Helen Rowe