Plans to build a business park on the site, including a cold storage warehouse and a Lidl branch, have sparked anger in a country that long neglected its Nazi past.
"For me, it's a sad feeling, because a place burdened by history is being built over, sacrificed to the economy," said Erich Strobl, head of a local campaign to preserve part of the site, told Agence France-Presse(AFP).
Once Austria was annexed by Nazi Germany in 1938, the Weinberglager complex held thousands of prisoners of war and forced laborers, later including the Hirtenberg subcamp of the Mauthausen concentration camp, Austria's second-largest women's camp.
Around 400 women, mostly from the Soviet Union, were imprisoned there from September 1944 to April 1945 and made to produce infantry munitions nearby.
Historian Bertrand Perz, who specializes in the Mauthausen camp, told AFP the site remains "historically important," noting that "women prisoners in Mauthausen have been marginalised in the culture of remembrance."
Plans to build a business park on the plot about 40 kilometers (25 miles) south of Vienna, including on land that once formed part of the concentration camp, were first revealed in 2024.
"A former concentration camp must not be built over with new structures," the International Mauthausen Committee said.
Josef Pumberger, a board member of the Mauthausen Committee Austria, told AFP that standing before the site, where grey columns already rise from the ground, he felt "grief, anger, rage, that something like this can happen in Austria in the year 2026."
The project has also attracted controversy because the land was previously owned by the local mayor, Andreas Ramharter, who sold it in 2022 and 2023 for more than €15 million ($17.5 million), according to local media reports. Ramharter declined to comment when contacted by AFP.