Bitcoin dropped below $US7,000 ($A9,800) to trade more than 5 per cent down on the day, having fallen by well over $US1,000 since hitting an all-time high on Wednesday.
On Friday Bitcoin dropped to $US6,800 on the Luxembourg-based Bitstamp exchange at lunchtime, before recovering a little to $US6,870 just over 20 minutes later.
On Wednesday, it had touched $US7,888 after a software upgrade planned for next week that could have split the cryptocurrency in two was suspended.
As bitcoin fell, Bitcoin Cash - a clone of the original that was generated from another split on August1 - surged, trading up as much as 35 per cent on the day at around $US850, according to industry website Coinmarketcap.
Despite losing almost 7 per cent this week, bitcoin is still up more than 600 per cent so far this year.
