National Union of Mine Workers general-secretary Inoua Neino told Reuters that the strike erupted due to failure of company in paying a bonus on the mine’s 2012 financial results.

"Work stopped on Thursday awaiting the resolution of our demands, principally the payment of a bonus of 600 000 CFA francs per worker on the 2012 financial results," said Neino.

Avera owns majority stake of 34% in the mine alongside Niger state with 31%, Japan-based OURD with 25% and Spain-based Enusa with 10%.

The strike comes at the time when French nuclear firm is looking to renew its long-term contracts for its Cominak and Somair mines in West Africa state.

"The conflict is due to the fact that Cominak has employed trickery," remarked Neino, adding that the company had reduced XOF10bn ($19.8m) from its total profits of XOF27bn ($53.7m).

However, Niger president Mahamadou Issoufou claims that the company has failed to obtain expected benefits from decades of uranium mining.