Sinn Fein has denied that the IRA made a threat to the sister of ex-informer Martin McGartland.
Informer Martin McGartland was given a new identity
Earlier this week the police warned the woman that republican paramilitaries had obtained details of her address.
The warning did not name any group, but Mr McGartland was an RUC Special Branch agent within the IRA in the late 1980s.
He has blamed the IRA for the threat but Martin McGuinness of Sinn Fein has claimed the move was aimed at damaging the political process.
"I don't believe for one minute that the IRA are involved in any way in any of this," he said.
"It is quite clear at key times in the process in the past... that there are people within the process who are doing their damnedest to try to destabilise the process and to undermine the republican contribution to it."
Mr McGartland said his sister was taking the warning seriously.
He said that there had been attacks on members of his family in the past and that he believed the British government was prepared to sacrifice former agents.
He said he believed pressure had been brought to bear to ensure that no-one was charged over a 1999 attempt on his life.
The IRA was blamed for trying to kill Martin McGartland then, when he was shot seven times.