File image: Proactiva Open Arms via AP.

Tunis - Tunisia's navy has recovered nine more bodies from a migrant boat that sank off the Tunisian coast this week, a humanitarian official said on Friday.

This brings the number of bodies retrieved so far in the incident to 72, according to Mongi Slim, the head of the Tunisian Red Crescent branch in the southern province of Medenine.

The boat sank off Tunisia's southern town of Zarzis on Wednesday while carrying 86 African migrants. Four of them were rescued at the time, although one died later in hospital.

Forty-seven bodies were recovered on Thursday after corpses floated to the water's surface, Slim told dpa. The dead included a child and five women, he added.

The boat had set sail for Europe on Monday from neighbouring Libya.

The Tunisian coast has become a common launch point for thousands of migrants, including Tunisians, seeking a better life in Europe.

In May, at least 70 migrants died after their boat sank off the Tunisian coastal city of Sfax.