Vice President Kembo Mohadi failed to appear before the Mines and Energy portfolio committee amid reports that he is not well.
Portfolio committee chairperson, Honourable Temba Mliswa announced in parliament on Thursday morning.
"VP Mohadi is not feeling well and is outside the country so he will not be appearing before the Mines and Energy Committee today," said Mliswa.
He added: "We wish him well'.
Earlier in the month, Mliswa told the media that the summoning of current and former high-ranking Government officials did not mean that they are guilty, but was only part of investigations into the alleged looting of diamonds at Chiadzwa during ex-president Robert Mugabe's rule.
"So we have asked for the former Minister of Home Affairs now Vice President Mohadi, former Minister State Security as well as Presidential Affairs Didymus Mutasa and the former Minister of Defence Sydney Sekeramayi," he said.
"We are not saying that they are guilty, but we would like to find out whether they knew about the concessions and who was running the concessions because all this information is very necessary.
"They have been summoned, they have received letters already and it's done. VP Mohadi, Dr Sekeramayi and Didymus Mutasa have received their letters. They are definitely coming."