"North Korea sent emails that could hack into cryptocurrency exchanges and their customers' private information and stole (cryptocurrency) worth billions of won," said Kim Byung-kee, a member of South Korea's parliamentary intelligence committee.
To put "billions" in perspective, 1 billion won equals $917,400.
Kim did not disclose which exchanges were hacked.
He added that the country's spy agency assumed that North Korea was continuously trying to hack into exchanges to steal cryptocurrency and that it was trying its best to prevent further hacking.
—CNBC contributed to this report