A German aid worker kidnapped in northwestern Somalia has been freed, his employer said on Wednesday.

"He's free and well," a spokeswoman for the German Agro Action (GAA), also known as Deutsche Welthungerhilfe, said, adding the man had contacted several colleagues in Somalia.

A spokesman for the German Foreign Ministry said the ministry had not yet had contact with the man.

The aid worker was kidnapped after gunmen ambushed his car on Tuesday in Era Gabo, a town in the breakaway republic of Somaliland.

The attack occurred in Sanag region, a disputed area that Somaliland and neighbouring semi-autonomous Puntland have long fought over.

Although Somaliland and Puntland have enjoyed relative peace compared to southern Somalia where the interim government is fighting an Islamist insurgency, the north has increasingly become associated with kidnappings for ransom.

Somaliland broke away in 1991 when warlords toppled military dictator Mohamed Siad Barre plunging the Horn of Africa country into anarchy. It has governed itself since, but its claim of independence has not been internationally recognised.