Pensioners have been given until Friday to register with the IKA social security fund as part of a census or face the prospect of not receiving their monthly retirement pay.
Speaking to Skai TV on Monday morning, IKA director Rovertos Spyropoulos said that so far 150,000 people who are receiving pensions have failed to register with IKA. He said that another 110,000 people who receive supplementary pensions have also failed to appear.
Anyone not registering by Friday will have their pension stopped, said Spyropoulos.
The IKA director said that he did not want to estimate at this moment how many of those who have not yet taken part in the census were receiving their pensions illegally.
A census of some 1.2 million Greeks who receive farming pension also began on Monday.