The unions, along with the Communications Workers Union, have been locked in discussions with the part state-owned fixed-line provider since March.
Marius Croucamp, spokesperson for Solidarity, told HumanIPO last month little progress had been made and the situation appears to be at breaking point now with regards to strike action.
Telkom is offering a reported 6 per cent wage increase while the unions are holding out for between 8 and 11.5 per cent.
SACU already has a strike certificate from the Commission for Conciliation, Mediation and Arbitration, while Solidarity is expected to apply for a similar certificate soon.