Zimbabwe's finance minister has refused to comment on where the First Family got its money to buy a mansion in South Africa and to import luxury cars.
Finance Minister Patrick Chinamasa told parliament he was "not aware" of any such purchases.
"I cannot comment on allegations which I am not aware of. These are transactions outside Government," the minister said, according to an official transcript of parliamentary proceedings.
"If they happened at all I cannot comment. You need to ask those you allege have done so," he added.
The finance minister was responding to a question from independent MP, Temba Mliswa on Wednesday.
The minister's comment came after recent reports in the private press that Grace Mugabe had recently bought a mansion worth R45 million in Johannesburg's plush Sandhurst district. Reports last week said her son Russell Goreraza (by a previous marriage) had imported a Rolls Royce (some reports said two).
The First Family has not responded to the reports.
Said Mliswa: "I would like to know whether the money that was used by the First Lady to buy a house in South Africa and equally the money used by Russell Goreraza to buy cars outside the country was priority and did it also have foreign exchange approval?"
'Hold everybody accountable'
The MP objected to Chinamasa's response, saying parliament could not have ministers who "duck and dive to protect corruption.
"This House must uphold the Constitution and must hold everybody accountable; the First Lady has been extravagant," added the MP, who vowed to bring "evidence" of the First Family's acquisitions to parliament.
Earlier this month local business executives warned that Zimbabwe's worsening foreign currency crisis would trigger shortages of food and other basic commodities.