Lumka Oliphant was invited to discuss a crisis over social security payments, amid fears that millions of vulnerable people could be cut off next month when a government contract expires.

The spokeswoman has been widely condemned on Twitter and accused of using distraction tactics.

A minority has praised her decision to respond in Zulu.

Of South Africa's 11 official languages, English is the most commonly used in official communications.

"Just for the benefit of all my listeners, could you please just respond in English?" Talk radio 702 host Xolani Gwala asks the Social Development Department spokeswoman after her initial answer.

Ms Oliphant had been invited on the show to discuss confusion over how millions of South Africans will access their social grant payments once the contract with the current provider, Cash Paymaster Services (CPS), expires at the end of the month.

"People want to know‚ will the grants be paid?" the host adds, before Ms Oliphant continues to respond in Zulu.

The host on the popular English-language radio station then brings the interview to an end after little more than a minute:

"If you don't want to talk I'm sorry‚ I'm going to have to move on because you clearly don't want to do this and you are determined to disrespect the medium."