The Gupta brothers have until the end of Monday to appear before Indian tax authorities to answer questions about their tax affairs, after missing two other summonses to appear, the SABC reported on Sunday night.
But sources say the Guptas are in Dubai, raising suspicions that they will once again fail to appear before authorities.
Their properties in India were raided last month, amid suspicions of money laundering.
After having the deadline to meet with tax authorities extended three times in as many weeks, the Guptas reportedly asked for another extension on Thursday last week. That extension ends at the end of Monday.
On previous occasions, the Guptas reportedly sent their accountant to appear before the authorities in their place.
According to the Mail & Guardian, Indian tax authorities confiscated documents relating to several properties owned by the Guptas, including 300 blank cheques in the possession of a family member. The documents reportedly reveal that the Gupta family has bought more than 120 properties since 2010. Authorities are also investigating a R200-million temple reportedly built in honour of their late father.
The Indian tax investigation will not affect the investigation by the South African authorities. Hawks spokesperson Hangwani Mulaudzi told Business Report that the Indian investigation was not related to its own investigation into state capture and that it was not connected to the investigation into Ajay Gupta, who has refused to hand himself over to the South African police.
A South African businessman spotted Ajay Gupta in Dubai last week. He said he would return to South Africa when "they give a reply", a presumed reference to requests by his lawyer to see the warrant of arrest issued against him. The Hawks have said they are not obliged to do so as the warrant is against Gupta, not his lawyer.