The Messel Pit, which contains 47-million-year-old fossil deposits, is located about 25km south of Frankfurt am Main, near Darmstadt, and was declared a heritage site in 1995.
The former site of an oil shale mine, it was opened to private prospecting after mining ceased in the 1960s.
It was proposed as a refuse dump in 1971, a threat that led to increased scientific prospecting and public concern.
A World Heritage Site is a landmark or area selected by the United Nations Educational, Scientific and Cultural Organisation (Unesco) as having cultural, historical, scientific or other form of significance and is legally protected by international treaties.
Department of Conservation senior international adviser Sarah Bagnall said a World Heritage site could only be nominated by a "State party", which in the case of New Zealand would have to be the Department of Conservation.
However, a proposal could first be investigated or developed by someone else, and would not be a quick process.
Any nomination would need to demonstrate how the site would be adequately protected and managed if the application was successful.
"The preparation of a nomination can take a number of years and the World Heritage Committee decision on it involves an 18-month evaluation process.
"A site must also be listed on a country's tentative list of potential world heritage sites for a year before it is nominated.
"If the nomination includes property that is not already protected, e.g. private land, the nomination would have to demonstrate how the site would be protected."
Protection could include private ownership with a conservation covenant, to protect valued features.
Sites were nominated for their values, therefore mining was "unlikely" to be compatible with world heritage status.
