Seven Welsh councils with holiday home hotspots are considering increasing council tax on second homes.
Ceredigion, Pembrokeshire, Anglesey, Conwy, Powys, Carmarthenshire and Gwynedd are exploring new powers to charge up to 100% extra.
The Welsh Local Government Association said it meant second homes could make a "fair contribution" to the community.
However, Gwynedd said a potential loophole could mean councils were worse off.
An estimated 23,000 homes in Wales are empty or used as second homes and the seven authorities currently consulting have about 16,000 between them.
Changes to the Housing (Wales) Act 2014 mean councils have the ability to charge a premium on top of the existing council tax payments for second homes from the 2017-18 financial year.
It is hoped it will help control house prices and bring empty properties back into use.
