The SA Revenue Service says it has contingency plans in place in case a planned major strike by bank employees goes ahead on Friday.
The strike against job losses is being organised by banking union Sasbo, which boasts of having 50 000 members.
The tax agency said in a statement on Tuesday that while it views the strike as unlikely, it is rolling out plans to make sure there is "minimal disruption to SARS services".
"In this respect, SARS will work with all role-players to avert any disruption to the country’s financial system. In view of this protest action, we request patience and understanding from taxpayers and traders." It did not say what the plans entail.
Several banks have also said they have contingency plans in place to try and continue operations if the protest action proceeds.
Business Unity South Africa, on behalf of the banking sector, has lodged an urgent application to interdict the strike. The matter is to be heard in court on Wednesday.
Sasbo, meanwhile, has warned South Africans to expect the banking sector to grind to a halt on Friday.
"Make sure you have enough money (cash) on Thursday," Sasbo general secretary Joe Kokela told Fin24 earlier in the week. "No one will be able to transact, unfortunately."
- Additional reporting by Lameez Omarjee, Helena Wasserman