The 37-year-old, who became the paper's first female lobby journalist three years ago, was arrested when she attended Bromley Police Station by appointment this morning.
She was arrested on suspicion of conspiracy to corrupt and suspicion of conspiracy to cause misconduct in a public office.
Ms Hartley is a long standing Sun reporter who has worked in Los Angeles for the paper and has also had spells as the consumer affairs correspondent and home affairs correspondent.
When she was appointed to the paper's lobby staff three years ago, the then political editor, George Pascoe-Watson described her as a "distinguished veteran news reporter with ten years experience on the road".
It is understood she has been on maternity leave from the paper in recent months.
She is the 30th person to be arrested as part of Operation Elveden, which was set up to investigate allegations that journalists had illegally paid police officers and public officials for information and stories.
The investigation, which is being supervised by the Independent Police Complaints Commission, is running alongside Operation Weeting which is examining phone hacking allegations at the News of the World newspaper.
A Scotland Yard spokesman said: "The 37-year-old woman attended Bromley Police Station by appointment and was arrested on suspicion of conspiracy to corrupt under the Prevention of Corruption Act 1906, suspicion of conspiracy to cause misconduct in a public office, contrary to Common Law and suspicion of bribery, contrary to the Bribery Act 2010."
In an internal memo to staff, News International chief executive Tom Mockridge said: "I am sorry to inform you that a further News International employee has been arrested by the police in connection with Operation Elveden."
He added: "As I have said before, it is important that proper due process takes its course and we must not prejudge the outcome of the police interviews. The company is continuing to do everything it can to assist our colleague, and has provided her with legal support. I appreciate this is difficult news for everyone and I am grateful for your continued hard work."
The arrest followed information that was passed to the police by News Corporation's Management and Standards Committee, set up by Rupert Murdoch in the wake of the hacking scandal last summer.
The company is carrying out internal investigations relating to Mr Murdoch's remaining UK papers - The Sun, the Times and the Sunday Times - and is working closely with the police team investigating alleged phone-hacking and corrupt payments to police and other public officials.
Among the arrests so far are a number of senior Sun journalists as well as police officers, members of the armed forces and a worker from HM Customs and Revenue.