Detectives from Operation Elveden arrested two men and woman at around 6am this morning (June 14) in Corby and Croydon.
Rupert Murdoch's News International confirmed to The Guardian that one of the individuals detained was a Sun journalist, bringing the number of current and former journalists at the paper arrested by Operation Elveden to 13.
In total, 33 people have been arrested by the investigation, which runs alongside the Operation Weeting probe into phone hacking.
Among the people arrested today is a 40-year-old former prison officer, who was held at his home in Corby, Northamptonshire, on suspicion of corruption and misconduct, along with money laundering.
A 37-year-old woman was also arrested in Corby and is suspected of aiding and abetting misconduct in a public officer, and money laundering.
Both are being questioned by officers at a police station in Northamptonshire.
A 31-year-old man was arrested at his home in Croydon on suspicion of conspiracy to corrupt and cause misconduct in a public office. He is being questioned at a south London police station.
In a statement, Scotland Yard said: "Officers investigating allegations of inappropriate payments to police and public officials have arrested two men and one woman this morning at three separate addresses.
"The arrests were made at approximately 0600 hours by officers from Operation Elveden which is being supervised by the Independent Police Complaints Commission (IPCC) and is being run in conjunction with Operation Weeting, the MPS inquiry into the phone-hacking of voicemail boxes.
"Today's arrests are the result of information provided to police by News Corporation's Management Standards Committee. They relate to suspected payments to a public official and are not about seeking journalists to reveal confidential sources in relation to information that has been obtained legitimately."
The arrests come on the day prime minister David Cameron gives evidence to the Leveson Inquiry on press ethics and standards on the relationship between politicians and the media.