Campaigners are calling for a “nationally significant” artwork in a redundant church to be given listed status.
The Crucifixion by artist George Mayer-Marton was created on the wall of the Church of the Holy Rosary in Oldham in 1955.
But, according to Save Britain’s Heritage, there are fears it could face vandalism, theft or demolition as the church has remained closed since 2017.
A spokesman for the conservation charity said it was backing calls to rescue the artwork and had written to Historic England urging them to recommend it was listed.
The Diocese of Salford, which owns the church, said it was committed to finding a new home for the work and had stepped up security around the site.
The mural includes a mosaic of the figure of Christ and paintings of Mary and John the Apostle on a background of blue.
The paintings, created using the technique fresco, where paint is put directly onto plaster, have since been covered over but campaigners hope the original work remains intact and could be restored.
Henrietta Billings, director of Save Britain’s Heritage said: “This is an incredibly rare, well executed and important mural for Oldham and for England by a leading 20th century artist and lecturer, it needs protection and national recognition through listing and Save is ready to help find a secure future for it.”
A spokeswoman for the Diocese of Salford said: “Since the closure of the Church of the Holy Rosary in 2017, protecting George Mayer-Marton’s rare work of art has been of paramount importance to us.
“We have taken action to improve the security of the building to ensure the safety of the work and have cooperated with parties who have shown an interest in it.
“The Diocese of Salford is committed to finding a new home for the work of art and we continue to explore options to find a place where it can be permanently displayed and made available to members of the public for years to come.”
Mayer-Marton, of Jewish-Hungarian origin, was a leading figure in the art world in Vienna, Austria, the 1920s and 1930s before he and his wife escaped to Britain in 1938.
In 1952 he became a lecturer at the Liverpool College of Art and while there was commissioned by the Roman Catholic Church to carry out works at a number of churches in Lancashire and Cheshire.
Another of his murals, the Pentecost, can now be seen at the Metropolitan Cathedral of Christ the King in Liverpool.
A spokesman for Historic England confirmed an application to list the church had been received and was being carefully considered.