BAMAKO (Reuters) - Mali, one of the world's poorest countries, has identified 13,000 fictitious workers on the state payroll who had cost a total of 30 billion CFA francs ($50 million), according to the information minister.

A source in the West African state's finance ministry told Reuters on Saturday these were mostly workers who had either died or left to go and work for international organizations. The source added that prosecutions could follow, but for the moment the priority was to get stolen money repaid.

The landlocked desert nation and an important gold exporter, Mali has suffered from endemic corruption and instability over the years, and more lately from multiple insurrections by Islamist groups in the north, as well as infighting between armed factions.

Information Minister Mountaga Tall made the comments about bogus state employees on state TV and radio late on Friday.

"The Foreign Minister conducted a physical control combined with paying in cash ... (and) detected about 13,000 staff that were either fictitious or irregular," he said.

"The savings that can be made if all measures are taken ... will be around 30 billion CFA francs," Tall added. He did not give a breakdown of the figure. The source at the finance ministry also could not provide such details.

Investigating and striking off ghost workers are among the requirements of Mali's program with the IMF.

(Reporting by Tiemoko Diallo; writing by Tim Cocks; editing by Mark Heinrich)