South African communications regulator Icasa said on Monday that the proposed tie-up between mobile phone group MTN and India's Bharti Airtel may need to be the subject of public hearings.
"MTN's licence is clear, if the transaction involves change in shares it needs to notify the authority before the transaction is concluded," said Sekgoela Sekgoela, Independent Communications Authority of South Africa spokesman.
"Once the authority has that information (details of any share transaction) it can determine whether the transaction will need to be subjected to a public process or not, it cannot do so until it has all the facts before it."
The deal is subject to an end-September deadline. The firms have extended talks twice.
Bharti has increased the cash component of its offer for a 49 percent stake in MTN to $10 billion from a proposed $7.6 billion, two people familiar with the matter said last week.
On top of that, Bharti would pay $4 billion in stock for a total package of $14 billion, 7 percent more than the earlier $13 billion proposed deal.
On Sunday, South African communications minister Siphiwe Nyanda expressed caution over the proposed transaction.
Any deal should take into account MTN as a "South African company with a footprint in Africa" and "we are interested that it should remain" here, said Nyanda.