Activists who claim Gwynedd is facing a second homes "crisis" have marched 20 miles (32km) after a recent increase in house prices.
About 60 people marched from Nefyn, on the Llyn Peninsula, to Caernarfon on Saturday.
Nefyn Town Council said house prices in the area had gone "through the roof" in recent months.
The Welsh Government said it recognised the challenges around second homes and was monitoring the law closely.
According to Gwynedd council's housing department, 811 new houses are needed each year to meet local demand. But it says 830 existing properties each year are those that qualify for the higher rate of land transaction tax, including second homes and buy-to-let properties.
Rhys Tudur, who sits on Nefyn Town Council, called on the Welsh Government to devolve the land transaction tax to local authorities, according to the Local Democracy Reporting Service.
He said: "We are being priced out of the very communities we were raised. It's been made impossible, thanks to the hike in house prices.
"From what we can see day to day, our communities are being swept away under our noses and the Welsh language is being dismantled and depleted to a great extent, and it's heart-breaking to see the inaction of the government so far."
Elfed Wyn Jones, chairman of the Gwynedd and Anglesey committee of pressure group Cymdeithas yr Iaith, said: "There's an urgent crisis in the functioning of the housing and property market - and whole communities are losing a large proportion of their homes."
The Welsh Government said: "We recognise the challenges second and empty homes can present to the supply of affordable housing in some communities in Wales.
"We're on target to deliver 20,000 new affordable homes this Senedd term, and Wales remains the only UK nation to have given local authorities powers to charge higher levels of council tax on both long-term empty and second homes.
"Our land transaction tax also includes an additional 3% charge for second home and buy to let purchases in Wales, and we recently changed our eligibility criteria for business support for self-catering properties."