The municipality therefore wants to levy steeper real estate tax on these flats starting 2020, in order to encourage fair business practices.
Aizkraukle municipality representative Olga Leitlande told Latvian Radio that the 600 flats make up about one fifth of the flats in the town.
Locals told Latvian radio that all the flats in a residential district seem to be inhabited.
"All the flats in our house are inhabited. If there's an empty one, it's quickly bought up, restored and people move in," said Valentīna, a local janitor.
Ads appearing on a popular classifieds website also testify that there's virtual equilibrium in supply and demand in the Aizkraukle housing market.
Einārs Zēbergs (Vidzemes party), vice-chairman of the municipal council, said that the housing market has in fact become more active recently.
"However, if flats have no legal resident but they are in fact inhabited, it causes losses to both the locals and the municipality," he said.
"The locals who aren't legally registered to live don't pay for waste management. Furthermore, they aren't included in estimates about water loss," Zēbergs said.
In order to counteract this trend, the municipality wants to introduce a 1.5% real estate tax on uninhabited flats. The current tax for all housing is 0.2% of its cadastral value.