Qatar Airways will take a 25% stake in South Africa-based regional carrier Airlink as both airlines seek to boost services and passenger numbers across Africa, they said on Tuesday.

Qatar Airways CEO Badr Mohammed Al Meer, speaking alongside Airlink's CEO Rodger Foster in Doha, told reporters the investment would boost Qatar Airways' access to passengers in regional cities in Africa.

Foster said it would allow privately owned Airlink to expand in Africa and eventually to operate larger aircraft on one or two routes. It would not expand beyond Africa, he said.

The executives did not disclose the value of the investment that was officially agreed on Tuesday, and Qatar Airways' Al Meer said it would require regulatory approval.

With a 25% equity stake in Airlink, Qatar Airways will take the maximum foreign ownership share that South African regulators allow for airlines, Foster said.

Airlink is currently owned by Foster's family, South Africa's Webb family and institutional investors Coronation Global and Sishen Iron Ore Company Community Development Trust, according to Foster.

Qatar Airways will gain two seats on Airlink's 14 member board and will have 25% shareholder voting rights, Foster told Reuters.

State-owned Qatar Airways holds stakes in British Airways-owner International Airlines Group, Latam Airlines, Cathay Pacific Airways, and China Southern Airlines.

It has also been in talks to acquire a minority stake in Rwanda's RwandAir and in 2019 agreed with the country's government to take a majority stake in a new international airport in Rwanda.

Airlink, which flies to more than 45 destinations in 15 African countries, and RwandAir both operate on several of the same routes.

"It makes sense that as Qatar Airways gets more involved in RwandAir, we start rationalizing the duplicated activity," Foster said, adding that though discussions have not started yet, it could mean an interline or code share agreement with the airline.

Airlink already has a code share agreement with Qatar Airways, which allows the airlines to sell tickets on flights operated by each other.

The African carrier has a similar agreement with Dubai's state-owned Emirates, a competitor of Qatar Airways, which Foster said would continue.