The agent of one victim said it is difficult what to do next and the people responsible are sick.
They said It can take years to pursue the matter and to get the content taken down from the internet.
Accessing and then leaking people's personal data is reprehensible, and they would urge everyone to take steps to secure their online accounts, a spokesman for the National Cyber Security Centre (NCSC) said.
The NCSC recommends people use two-factor authentication where available.
The owners of iCloud, Apple, have yet to comment on the leak.
The news follows confirmation from Manchester United that they had been targeted in a cyber attack described as 'a sophisticated operation'.