South African Airways (SAA) has suspended wage negotiations with transport union the South African Transport and Allied Workers' Union (Satawu) because of intimidation and violence.
Technicians and maintenance employees began striking on Monday to demand higher salaries.
The union is demanding a 12 percent increase while SAA is offering 6 percent.
Earlier this morning, police reported that scores of protesters had partially blocked the Jones Road off-ramp, near to SAA’s offices in Kempton Park, disrupting traffic.
But Satawu has denied that its members were involved in the protest.
SAA spokesperson Tlali Tlali says negotiations can only resume once Satawu has disciplined its members.
"Until Satawu has satisfied the requirement of ensuring that all acts of intimidation and all acts of inconvenience on public roads have come to an end, SAA management will not sit around a negotiating table with them."
Meanwhile, SAA has claimed it can't afford the demands of the workers given the economic climate.
Strike could spread
Earlier this week, Satawu warned the strike could spread to other airports around the country.
Satawu's Vincent Masoga said while the union's representation at other airports isn’t as strong, it's confident other workers will down tools in solidarity.
"Of course in other areas such as Cape Town and Durban the momentum may be slow to take on, but they are definitely going to be participating."
Tlali said the airline's contingency plan was comprehensive enough to deal with this if it happened.
"We are confident we should be able to continue with our operations for as long as the industrial action takes."