National Transport Movement (NTM) members at the national airline and the state-owned rail agency started a strike on Friday, officials said.
NTM deputy general secretary Liver Mngomezulu said both SA Airways and the Passenger Rail Agency of SA (Prasa) were refusing to recognise the union.
He said around 220 SAA workers had gathered at the airline's head offices in Johannesburg at 8am.
“We are expecting all 1300 of our members to take part in the picketing... We just had minor delays because of the rain, but we should all be here by around 10am,” he said.
“Members of rival unions have also said they will join us.”
On Monday, SAA reported it was prepared for the strike and had put in place contingency plans to ensure minimal disruptions.
The airline has around 11,000 employees.
Mngomezulu said he was certain the strike would cause flight disruptions.
“Last time we embarked on a two-hour strike and several flights were delayed and cancelled, so we are expecting even more to happen today, since we will be here the whole day and we will stay here until the SAA management decides to recognise us,” he said.
The NTM has alleged that SAA management refused to recognise it as a workers' representative even though it had surpassed the number of candidates needed for them to be validated.
SAA spokesman Tlali Tlali dismissed their claim in a statement on Thursday.
“NTM relies on a claim that its membership is more than 1300. Their membership is inclusive of employee categories that are not provided for in the bargaining forum constitution.”
In the railway industry, NTM claims a 4000 membership at Prasa.
Mngomezulu said he was expecting all of the members to take part in protests at the agency's head office in Braamfontein and at another protest in Bosman, Pretoria on Friday.
Prasa spokeswoman Lillian Mofokeng said the agency was not expecting any disruptions to train operations.
“Out of our 5600 employees in Gauteng, only 51 haven't reported for duty this morning,” said Mofokeng.
She explained that NTM needed to follow the right channels in order to have the union recognised.
“They need to have a certain number of members before they can be recognised. They report that they do have these numbers, but we need to first verify these claims,” she said.
Mngomezulu accused Prasa of deducting money from their union members for another union's membership.
“They are deducting our people's subscription for rival unions... That is unacceptable,” he said. - Sapa