The Cofiwch Dryweryn wall was repainted last year after being defaced
An appeal is being launched to save a piece of graffiti which was daubed on a wall after a Welsh village was flooded to provide water for Liverpool.
The unofficial memorial near Aberystwyth reads Cofiwch Dryweryn (Remember Tryweryn), a small community near Bala which disappeared in 1965.
It is deteriorating and last year was defaced and then repainted.
Cadw, the historic monuments agency, has already donated £30,000 to the appeal, but another £50,000 is needed.
Heritage Minister Alun Ffred Jones is helping to launch the appeal at the National Eisteddfod in Bala.
Llanrhystud Community Council is behind the project to raise money to secure the long-term future of what some in the area describe as a "national landmark".
The graffiti was inscribed on the gable end of a derelict cottage and has faded and been repainted several times over the decades.
But it is deteriorating and has become a danger to the public. Parts of the lettering of the painted slogan are also rapidly disappearing.
The community council and local county councillor Rowland Rees-Evans are launching the appeal.
Mr Rees-Evans said: "The Tryweryn wall is a key landmark on the outskirts of our village and we are aware there is considerable support across Wales, and beyond, to ensure its future .
"It has national significance to the contemporary political life of Wales.
"The community council does not have the necessary resources to carry out the repair work or to ensure future maintenance in order to safeguard this iconic wall for future generations.
"The wall was inscribed by the people of Wales reacting to actions they felt unjust and it is therefore appropriate that the wall is owned by the people of Wales."
Project leaders said £80,000 had to be raised to "establish ownership, preserve and maintain the wall".
The heritage minister said: "I'm delighted that the Welsh Assembly Government through our historic environment division - Cadw, has been able to kick start this appeal, I'd like to congratulate the Llanrhystud Community Council for taking this initiative and wish them well with the appeal."