Northern Secretary Shaun Woodward is said to be considering a challenge to the proposed early release of the loyalist who murdered two friends in a Co Armagh pub in 1998.
Stephen McClean, a member of the splinter paramilitary group, the Loyalist Volunteer Force (LVF), is serving a life sentence for the killings of Damien Trainor and Phillip Allen as they had a drink together.
They were life-long friends and their deaths prompted outrage.
The Sentence Review Commission indicated last week that it may release McClean but not Noel McCready, another LVF man, who was also jailed for the shootings.
Damien Trainor's father, Seán, and public representatives have criticised the possibility of an early release. The Prison Service suggested yesterday that any decision to release McClean could be challenged by Mr Woodward.
A spokesman said Mr Woodward "is considering the facts and will make a determination in the next few days".