More than 1,700 council workers across the Westcountry are on controversial "zero hours" contracts that have been condemned by unions and face a Government investigation.
Business Secretary Vince Cable last week announced he is reviewing the growing use of "nil hours" contracts amid fears low-paid workers are being exploited.
The controversial deals mean employees are not given fixed hours for working but are used as and when needed.
Councils defended their use, allowing flexibility when services come under pressure in summer, when millions of tourists visit the region. But some councils are reviewing the growing trend.
Stuart Roden, South West organiser for Unison union, said: "Zero hours are effectively slave labour and the worst kind of exploitation for those forced into this kind of employment as they, demand staff to be totally subservient and to be available 24-7 but without any guarantee of income.
"It means that employees cannot obtain normal credit arrangements or mortgages and property rental become problematic as they have no proof of regular income.
"Many are forced into 'pay day loan' arrangements and forced into debt and live at best hand to mouth.
"Our position is that no public authority should use zero hours contracts that demand the worker to be restricted solely to that employer and at their exclusive 'beck and call'."
Dorset County Council has more than 620 zero hours staff.
At Cornwall Council, around 300 staff are workers engaged on the contracts and a further 134 workers in local authority-maintained schools are on the deals. They include staff working in planning, social work and adult education.
In Devon, the county council employs 179 staff have "nil hours" contracts.
Teignbridge Council has 183 zero hours staff in them, including swimming teachers, estates surveyor and legal assistant.
Torbay Council says it has 139 staff employed on the contracts. Also, 116 Torbay staff are employed on fixed hours contracts who also take additional work where there are no set hours. For example, a library worker on 21 hours per week who is also required within theatres with no set hours.
Some 106 staff at West Dorset Council are on zero hour contracts in roles chiefly involved in leisure and tourism.
The figures were released to the WMN under the Freedom of Information Act.
Councillor Jeremy Rowe, Liberal Democrat deputy leader of Cornwall Council, said: "These staff are employed mainly within three areas – registration services, adult education and the music service – where they enable the council to respond to fluctuating demand for services and avoid relying on agency workers.
"While some workers appreciate the flexibility provided by a zero hours contract, we recognise that the fluctuating nature of the contracts does not provide the same financial stability and security as employment contracts with defined working hours.
"We are concerned to ensure that our use of zero hours contracts operates in the mutual interests of the workers concerned, the council and, of course, council taxpayers and service users.
"As a result some weeks ago the Cabinet initiated a review of the zero hours contracts inherited from the previous administration. Once completed, the results of this review will be considered by the Cabinet."
Conservative councillor Mike Walters, Teignbridge District Council's executive spokesperson for corporate services, said: "Casual jobs involving 'zero hour' contracts can provide a great deal of flexibility.
"It's important to remember there is no requirement on any member of staff to accept the work offered and equally, there is no commitment on an employer's part to offer any work.
"They help authorities like Teignbridge manage its workforce during peaks and troughs in demand – crucially in leisure services which fluctuate during the seasons – and to cover any absences.
"It is a two-way arrangement that can suit both parties if, and when, they are considered necessary and we always try to ensure they are used appropriately."
The Business Secretary told Lib Dem activists that the consultation would focus on the issue of "exclusivity" where workers on zero hours contracts are banned by their employers from seeking work with other firms.