The psychologist behind an app that harvested data from up to 87 million Facebook users has defended his role in the scandal, saying he "never heard a word" of opposition from the social media giant.

Steinhoff shares fell as markets reacted to the global conglomerate's annual general meeting which took place in the Netherlands on Friday.

The JSE opened the day firmer, with rand hedges leading the way as the dollar advanced against most major currencies, sending emerging markets and commodity prices spiralling lower.