A few crumbling concrete blocks in an overgrown field are all that remains visible of what was once a sprawling Nazi forced labour complex around the Austrian town of Leobersdorf.

Now, plans to build a business park on the site, including a cold storage warehouse and a store operated by the discount supermarket chain Lidl, have sparked anger in the Alpine nation, which long neglected to address its Nazi past.

"For me, it's a sad feeling, because a place burdened by history is being built over, sacrificed to the economy," Erich Strobl, head of a local campaign to preserve part of the site, told AFP.

After Nazi Germany annexed Austria in 1938, the Weinberglager complex was used for thousands of prisoners of war and forced labourers.

It later included the Hirtenberg subcamp of the Mauthausen concentration camp — one of Austria's largest camps exclusively for women.