Ethiopian Airlines says it's co-operating with an investigation by Zambian authorities after one of its cargo planes mistakenly landed at an airport still under construction near the capital, Lusaka.

Zambian air traffic controllers at the intended airport, 15 kilometres (9 miles) away, were quoted as telling the pilot that they couldn't see his plane when he informed them he was about to land.

"When he was about to land he was communicating with the radar, and they told him: 'We can't see you,'" the transport ministry's permanent secretary, Misheck Lungu, told AFP news agency on Monday.

Ethiopian Airlines said that pilots had not been told about a new airport with the same runway orientation as the existing one.

The Ethiopian plane was later flown to its original destination.