Sources at the Public Power Corporation said on Wednesday that they are waiting for instructions from the Finance Ministry regarding the collection of the emergency property tax.
A first instance court ruled on Tuesday that it is illegal for the tax, which was introduced last year, to be levied via electricity bills.
PPC is waiting to hear from the government whether it should continue to collect the tax.
In an interview on Skai TV on Tuesday, Finance Minister Yannis Stournaras said that the government would appeal the court ruling.
PPC said that some 350,000 customers had not yet paid the emergency property tax this year.