Germany's foreign minister has expressed regret over the fact that his country's diplomats failed for years to act on abuses at a secretive German colony in Chile.

For three decades from 1961 onward the enclave of Colonia Dignidad, or Dignity Colony, was the site of torture, slavery and child abuse.

The enclave's history features in a recent movie starring Emma Watson and Daniel Bruehl.

Foreign Minister Frank-Walter Steinmeier says the German embassy's failure to help people who fled the colony was "no glorious chapter" in his country's diplomatic history.

Steinmeier said Tuesday that he has ordered documents about the colony until 1996 to be unclassified for research purposes.

The case will also be used to teach young German diplomats how to act in sensitive situations.