Health Minister Aaron Motsoaledi ordered his department on Monday to stop distributing the kits, health spokesperson Fidel Radebe said on Monday.
Radebe could not say how many of 4.5-million testing kits bought by government had been distributed before media reports revealed last week that the WHO had ruled them unreliable in January.
"My impression is it was not in all the provinces. National treasury is looking into the matter and the department should be able to say by Friday what is happening."
Treasury spokesperson Jabulani Sikhakhane has told the media a decision was taken at the weekend to probe how the R22.5-million tender for the testing kits was awarded.
The Democratic Alliance said the purchase of the testing kits had created a health risk in a country with more than five million HIV positive people.
"One of the key strategies for combating HIV is the drive to know your status. This facilitates timeous treatment and decisions on safe sex," DA spokesperson Patricia Kopane said.
"The minister must be held accountable for placing South Africans at risk, even through his ignorance." – Sapa