Just 14 percent of unvaccinated Greeks aged 60 and above paid the administrative fine imposed by the government in January, according to data from the Independent Authority for Public Revenue (AADE).
Holdouts were fined 100 euros a month (in January the fine was 50 euros as the measure went into effect mid-month) in a bid to boost lagging inoculation levels and ease pressure on healthcare amid the coronavirus pandemic.
However, of the 317,962 individuals notified by tax authorities to pay the fine, only 44,000 had done so by the March 15 deadline.
A late payment surcharge will be applicable in these cases. Outstanding debtors face confiscation of property assets.
An unspecified number of unvaccinated individuals have challenged the fine with their local tax authorities, although there is no such legal provision.
The fines for unvaccinated over-60s will be terminated in mid-April, the government said last week.