The main body representing the hospitality industry in Namibia says it is "appalled at the disrespect" shown by foreign tourists who sprayed graffiti on one of the country's historic buildings,The Namibian newspaper reports.

Gitta Paetzold, the CEO of the Hospitality Association of Namibia (HAN), told the paper they discovered the damage on the abandoned Garub Rail Station - located in the Namib, the oldest desert in the world - when images were shared on social media last week.

Garub Rail Station, a popular sighting spot for wild horses of the Namib, is not listed as an official heritage site.

However, it is protected under the National Heritage Act because it is in a conservation area, the Namib-Naukluft Park, which includes part of the desert, The Namibian reports.

HAN said Namibians should take a stand against vandalism to show they care for the environment and the country's heritage.

Some activists on social media are calling for the removal of the graffiti.