A new report suggests PCSOs in Herts are being used to cover duties that would traditionally have been conducted by fully trained police officers.
The role was created in 2002 to provide a visible uniformed presence to neighbourhoods and town centres up and down the country.
Police Community Support Officers were given limited powers, such as directing traffic.
But Her Majesty’s Inspectorate of Constabulary (HMIC) now says that of the UK’s 43 forces, 17 may be using them for duties beyond their role or training.
This includes being sent to deal with and investigate crimes.
But Herts Police spokesman Colin Connolly defended the practice.
He said: “One of the forces that uses PCSOs for investigations is Hertfordshire – but they do not work on their own.
“They are part of safer neighbourhood teams working alongside police officers and they do not take the role of a trained detective.
“They get to know local people, local youths and who can be potential trouble-makers and who cannot.
“They really get under the skin of a local area.
“For instance, if there’s some CCTV footage of graffiti, they could be the best people to look at it – because they will recognise the people in that CCTV footage or the people in the background of it.”