Almost sounds like a shanty, or maybe a work-song. That would fit with the location:-
http://en.wikipedia.org/wiki/Kilindini_Harbour
Many other versions on YouTube.

Lyrics from here seem to accord with umpteen other lyric sites (no author attributions found):-

http://10000lyrics.com/lyrics-madi-madi-song-peggy-march-227066.html

Madi-madi song

Madi madi madi
Madi madi madi
Madi
Madi
Madi madi madi
Kilindini Docks
Balla balla balla
Balla balla balla
Madi no guenda, Kilindini Docks

(Madi no guenda, Kilindini Docks)
(Madi no guenda, Kilindini Docks)
Deep in the jungle, along the riverside
(Madi no guenda, Kilindini Docks)
Men keep on working, morning to the night
(Madi no guenda, Kilindini Docks)
Kerry and Gary can't carry that cable
(Madi no guenda, Kilindini Docks)
You can hear them singing sad and lonely songs
(Madi no guenda, Kilindini Docks)
Oh mister captain, that sun is very warm
(Madi no guenda, Kilindini Docks)
Oh mister boatsman, my heart's no longer strong
(Madi no guenda, Kilindini Docks)
(Madi no guenda, Kilindini Docks)

Madi
Madi
Madi

(Oh mister captain, the sun is very warm)
(Madi no guenda, Kilindini Docks)
Deep in the jungle, along the riverside
(Madi no guenda, Kilindini Docks)
Men keep on working, morning to the night
(Madi no guenda, Kilindini Docks)
(Madi no guenda, Kilindini Docks)

Madi no guenda, Kilindini Docks
(Madi no guenda, Kilindini Docks)
(Madi no guenda, Kilindini Docks)
Madi madi madi
Madi madi madi