The 47-year-old woman who has been arrested in Essex under Operation Weeting is understood to be Cheryl Carter, a former personal assistant to News of the World editor Rebekah Brooks.
Carter is said to have worked directly for Brooks, former managing editor Stuart Kuttner and former executive editor Neil Wallis who have all been arrested under Operation Weeting.
Carter was the 17th person to be arrested by Weeting officers. The operation was set up by the Metropolitan Police to investigate the media phone hacking scandal.
The woman has been held in custody at an Essex police station following her early-morning arrest at her home.
Operation Weeting works alongside Operation Elveden, which investigates claims that members of the media have been making illegal payments to the police.
Met Police commissioner Paul Stephenson and assistant commissioner John Yates have resigned over the investigations. Rupert Murdoch's News of the World closed down in summer 2011 after 168 years.