Four people have issued High Court claims against the Daily and Sunday Mirror and The People.
The claims allege "breach of confidence and misuse of private information" relating to the "interception and/or misuse of mobile phone voicemail messages and/or the interception of telephone account".
The Financial Times reports that no particulars of the claims have been filed as yet.
The four claimants, represented by media lawyer Mark Lewis, who also represented other celebrities and claimants in action taken against News International, have four months to serve claims on Trinity Mirror, the newspaper said.
More top news
Doctors should stop telling people to "complete the course" of some antibiotics, a group of experts have warned.
Around 40 events will be staged across the UK today as nurses step up their campaign for the Government to end the cap on public sector pay.
Within the next seven days, we are going to witness some of the most significant change in the British Monarchy for many years.