The authorities in Cameroon have discovered that they are paying civil service salaries to 45,000 employees who do not actually exist.
The "ghost workers" were uncovered by a census of public servants as part of a drive to stamp out corruption.
Finance Minister Polycarpe Abah Abah said the fake employees were costing nearly $10m (£5m) a month.
Earlier this year foreign donors made tackling corruption a condition for cancelling billions of dollars of debt.
"These people have been robbing the state," said Mr Abah Abah, adding that further cases could emerge as the census continued.
The government, he added, would take legal action against people making fraudulent claims for civil servants who had moved abroad or who were dead.
Other "ghost workers" include some of the 50,000 civil servants made redundant in the mid-1990s under pressure from the World Bank and International Monetary Fund.
Corrupt staff managed to get the names of some of these back on the payroll, officials were quoted by Reuters news agency as saying.
In 2005, the public service ministry found more than half of its 2,700-strong workforce did not exist.
Cameroon's progress as a state has been hampered by a level of corruption that is among the highest in the world.