Passenger planes from Portuguese carrier TAP and Ethiopian Airlines were involved in a near-miss over the Democratic Republic of Congo, government sources said Saturday.

"Very alarming information in my possession indicates (there was) a very high risk of disaster in the airspace of our country," Transport Minister Cherubin Okende Senga said in a letter seen by AFP.

He said the incident occurred on Wednesday and involved two aircraft of Ethiopian Airlines and TAP on international flights "which narrowly avoided colliding at the intersection of two air routes above" the city of Lubumbashi.

It said the near-miss occurred "because of the lack of communication between the crews and the Lubumbashi airport", according to the letter dated May 20 and addressed to the director of the country's air transport authority, the RVA.

The Ethiopian airliner was headed from Addis Ababa to Windhoek in Namibia, and the TAP jet was flying to Lisbon from the Mozambican capital of Maputo.

"The two routes converged above LUB (Lubumbashi). The two planes were already in the non-separation zone for less than 10 minutes." 

He warned that the relay antennas in the towns of Kalemie and Kamina could be down.

Given the "risks of disaster", the minister called for reports into the incident and into "the whole situation of regarding airspace" in the DRC.

Bordering nine countries and with a vast territory of 2.3 million square kilometres (88 million square miles), the DR Congo has a central position in the African continent.

The eighth-poorest country in the world despite immense resources, DR Congo has been mired in conflicts and political crises over the past 30 years, with chronic corruption and infrastructure often in an advanced state of disrepair.