African leaders are expected to hold a summit on July 21 to discuss a controversial mega-dam on the Nile River that has caused tension between Egypt, Ethiopia and Sudan, the South African presidency said Monday.

The meeting will be organised under the auspices of the African Union (AU), which South African President Cyril Ramaphosa currently chairs.

The Grand Ethiopia Renaissance Dam (GERD) has been a source of friction in the Nile River basin ever since Ethiopia broke ground on the project in 2011.

Sudan and Egypt view the dam as a threat to essential water supplies, while Ethiopia considers it essential for its electrification and development.

Ramaphosa's spokeswoman said the Bureau of the Assembly of the AU Heads of State and Government would hold a "virtual meeting" to discuss the dam on Tuesday.

"The meeting is a follow-up on the Bureau meeting on GERD that was held on June 26," spokeswoman Khusela Diko told AFP.

"During that meeting it was agreed that the Bureau will assess the progress regularly and chart the way forward on the AU-led process of the GERD negotiations accordingly."

Multiple rounds of tripartite talks on the $4.6-billion project have ended in deadlock.

Last month, Egypt accused Ethiopia of "intransigence" and appealed for the United Nations Security Council to intervene.

Cairo, Khartoum and the Arab League have since asked Addis Ababa to delay filling the dam reservoir until a comprehensive deal is reached.

Ethiopia, however, said it was on schedule to begin the filling in July as planned — though an exact date has not yet been set.

The 6,600-kilometre-long Nile is a lifeline supplying both water and electricity to the 10 countries it traverses.

A Sudanese official told AFP the dispute should only be resolved "by negotiation”.

"Every country has to benefit without harming the other,” the unnamed source said on Monday, adding that Sudan did not support calls for a UN intervention.

"Ninety per cent of the issues have been agreed and we believe that 10 per cent of the pending issues can be solved.”

The UN has called on the three countries "to work together” to resolve their differences on the project.

Leaders from the Democratic Republic of Congo, Egypt, Ethiopia, Kenya, Mali, South Africa and Sudan are set to take part in the meeting on Tuesday.

AU Commission Chairman Moussa Faki is also expected to attend, as well as United States, European Union and World Bank observers.