Controversial outsourcing Bromley council faces strike action by workers at two of its contractors that could hit libraries and care services.
The ballots for strike action are by 36 workers at 14 libraries employed by Greenwich Leisure Ltd (GLL) and 20 care workers working for Certitude Support.
The ballots come as the whole question of the outsourcing of public services is being put under the microscope, following the Carillion debacle.
Unite regional officer Onay Kasab said: "Tory-controlled Bromley council has been a major cheerleader for the privatisation of public services, but GLL and Certitude Support have failed, hence the two strike ballots.
"The GLL ballot is about staffing, pay and time off for union duties. Staff are at breaking point and GLL has stated that posts will be cut. We have asked for numbers of those earmarked for redundancy, which it has not yet provided.
"Certitude has refused to recognise the union or to discuss pay. In addition, staff have persistently raised maintenance issues with serious health and safety implications.
The Certitude ballot runs from 25 January to 12 February and voting on action at GLL opens on 26 January, closing on 13 February.