According to a statement from Nehawu, deadlock was reached on April 19, following which Nehawu was issued with a certificate to strike by the Commission for Conciliation, Mediation and Arbitration (CCMA).
Nehawu said its members at the university had held two meetings over the past week in order to receive a mandate and map a way forward after the deadlock.
The union's demands to the university included an initial 10% salary increase, but which it had subsequently moved to 8%, this while the university was offering 7% plus R3,000 once off.
In addition to a demand for 13th cheques, Nehawu was also demanding more medical aid scheme options, as workers had said that the current one was too expensive.
"Failure to resolve these issues in the next coming few days, workers will be left with no option but to go on a full-blown strike," the union said.