Press Association royal reporter Laura Elston was arrested at a central London police station on Monday around 3 pm on suspicion of illegally accessing voicemail messages.
The 34-year-old journalist has now been released on bail.
Scotland Yard said Elston was questioned about intercepting communications in violation of section 1 of the Regulation of Investigatory Powers Act 2000.
Her bail came with a conditional reappearance date in October.
It has not been confirmed if Elston is connected to the News of the World, the newspaper that has become the focus of Operation Weeting.
The Metropolitan police launched Operation Weeting in April, after receiving "significant new information" about the News of the World phone-hacking claims from News International.
In April the News of the World senior reporter James Weatherup was arrested, but released after questioning. The paper's chief reporter Neville Thurlbeck and assistant editor Ian Edmondson were also held in April and released on bail with a conditional April return date.
Last Thursday a 39-year-old woman was arrested on suspicion of conspiring to intercept communications in violation of section 1 of the Criminal Law Act 1977. She was released the same day after the Scotland Yard questioned her at a West Yorkshire police station, though she must return to the station in October as well.
There is speculation that this woman is Terenia Taras, a freelance writer who has worked with the News of the World for years, although this theory remains unconfirmed by the Scotland Yard.
On Wednesday Metropolitan police commissioner Sir Paul Stephenson assured the public that the Operation Weeting team is still investigating the phone hacking scandal and providing information for the civil court claims.