Irish republican leader Gerry Adams will not be charged in connection with the IRA murder of a Belfast mother of ten in 1972, Northern Ireland's state prosecutors have announced.

Following a police investigation, the Public Prosecution Service said on Tuesday that the evidence against seven people including the Sinn Fein president was not strong enough to justify charges.

Adams, who played a key role in the Northern Irish peace process, was arrested and questioned for four days in May 2014 over the abduction and murder of Jean McConville.

The Irish Republican Army paramilitary group wrongly accused McConville of being an informer for the British army, but did not admit her murder until 1999.

Her remains were found in 2003 on a beach. She had been shot in the head.

Sinn Fein was the political wing of the IRA, which disarmed in 2005.

Adams, 66, has always denied being an IRA member.

"There was never any real basis for questioning me in respect of this case," he said on Tuesday.

"I played no act or part in Jean McConville's death."

Pamela Atchison, the deputy director of public prosecutions, said the evidence reviewed was "insufficient to provide a reasonable prospect of obtaining a conviction against any of them for a criminal offence".

The McConville case was reopened in 2013 when Northern Irish detectives obtained tapes of former IRA members speaking about the execution.

One man, Ivor Bell, was arrested in March 2014 and is currently before the courts, charged with soliciting McConville's murder.

McConville's son Michael said he was "shattered" by the decision not to charge Adams or the six others.

"We will continue to seek justice for our mother and see those responsible held to account no matter how long it takes," he said.