Cymdeithas yr Iaith has warned that there will be no radical action to solve the housing crisis in Wales and protect Welsh communities unless people come in large numbers to the Nid yw Cymru ar Werth (Wales is Not For Sale) rally in Blaenau Ffestiniog on May 4 to show the strength of feeling.
There are concerns among language campaigners that the Government does not understand the extent of the crisis facing Welsh communities, and that progressive policies to get to the root of the problem will not be adopted.
In a call to supporters of the campaign for a Property Act, one of the organisers of the rally, Osian Jones, said:
"In meetings with officials from the Welsh Government's Department of Housing and Planning, Cymdeithas yr Iaith has been very disappointed with the lack of understanding of problems facing local people when trying to find homes at an affordable price in their community, and the lack of understanding of the breaking up of Welsh communities.
"Unless there is great pressure on the Government before the summer, there is a real danger that the Government's White Paper on Housing will not make a real difference to our communities. In practice, this is the last opportunity during this Senedd term to introduce and pass legislation that will control the housing market for the benefit of local people and plan new developments according to the needs of our communities.
"After decades of campaigning and decline in our communities, radical action is needed now. Our call will therefore be "Property Act - Nothing Less Will Do", and the hope is that Stiniog and the surrounding areas of Traws, Penrhyn, Port, Penllyn and Dyffryn Conwy will lead the way and that everyone who is concerned about the future of our communities Welsh come in their hundreds or thousands to the rally."
The rally, which is being held on International Workers' Day, comes a few months before the Welsh Government publishes its long-awaited White Paper on "The Right to Adequate Housing" and before the Commission for Welsh-speaking Communities chaired by Professor Simon Brooks publishes its final report.