The chairperson of the parliamentary inquiry into Eskom said on Wednesday it proved impossible for the sheriff to serve summonses on the Gupta brothers to oblige them to testify on State capture at the power utility.

Zukiswa Rantho said summonses were issued by the secretary of Parliament to be issued to Ajay, Atul and Tony Gupta, as well as former president Jacob Zuma's son Duduzane and former South African Airways chairperson Dudu Myeni.

In the case of Myeni, the security staff at her home refused to accept the summons and the sheriff posted it to the gate last Wednesday.

On the same day, the sheriff attempted to serve summonses on the Gupta brothers and Duduzane Zuma, but in the case of the Guptas they could not be located at their residence.

"With regard to the Guptas, the Sheriff could not serve the summonses at their residence."

Rantho added: "The committee will engage with other law enforcement agencies such as the Hawks to assist in locating the witnesses so that the summonses can be issued by the sheriff.”

She said a meeting of the public enterprises portfolio committee conducting the inquiry on Wednesday had been cancelled because the summonses could not be delivered to the brothers, who are at the centre of allegations of the abuse of political influence to secure contracts worth billions from state-owned companies like Eskom.

The Gupta brothers, who were close to Zuma, are rumoured to have left the country. They have also been called to appear before Indian tax authorities to answer allegations of money laundering and tax evasion.