The former editor of the News of the World and her husband Charlie, the racehorse trainer and Telegraph columnist, were arested at their home in Chipping Norton, Oxfordshire, sources said.
Ms Brooks, a former editor of The Sun, had been on bail after being questioned by detectives last summer on suspicion of phone hacking and corruption.
Police from Operation Weeting arrested six people at addresses in London, Oxfordshire, Hampshire and Hertfordshire.
The five men, aged between 38 and 49, and one woman, aged 43, were arrested on suspicion of conspiracy to pervert the course of justice.
The co-ordinated arrests were made between 5am and 7am by officers from Operation Weeting, the Metropolitan Police's investigation into the illegal interception of voicemails.
They are being interviewed at police stations in Buckinghamshire, Oxfordshire, and central, east and south west London.
Officers are searching the properties where the arrests were made.
One man, 48, was arrested at a business address in east London.
The 43-year old woman and the 49-year old man were arrested at their home addresses in Oxfordshire and are being interviewed at separate police stations.
It takes the total number of arrests under Operation Weeting to 23.
The investigation was launched in January 2011 after the Metropolitan Police received new information from News International, the publishers of the News of the World, the Sun, the Times and the Sunday Times.
It is being led by deputy assistant commissioner Sue Akers and has 91 officers working on it.
Previous arrests under Operation Weeting include Ian Edmondson, the former News of the World assistant editor; Neville Thurlbeck, the former chief reporter; Neil Wallis, the former executive editor; Rebekah Brooks, the former News International chief executive; and Stuart Kuttner, the former managing editor.
Previous Operation Weeting arrests for conspiracy to pervert the course of justice include Cheryl Carter, the long-standing PA to Rebekah Brooks; Glenn Mulcaire, the private investigator; and Ross Hall, the former NOTW reporter.
