David Cameron says royal pardons difficult decisions taken by previous governments
The prime minister has said the granting of royal prerogatives to terrorist suspects were difficult decisions taken by previous governments.
David Cameron told the Commons he did not want to unpick those decisions.
He was responding to the revelation that royal pardons were given secretly to paramilitaries in NI in return for information.
The cases date as far back as the 1980s.
In the Commons on Wednesday, the DUP MP Nigel Dodds called on the government to name those who had been given pardons.
He said they should be named in the "interests of openness" and justice.
The prime minister said he would consider Mr Dodds request.
On Tuesday, the Northern Ireland Secretary Theresa Villiers said it would be wrong to name those granted a royal prerogative of mercy in terrorism-related cases.
Speaking on BBC Radio 4's File on 4, she said there was an argument for making details public in future cases.
Her comments followed revelations that royal prerogatives of mercy were used in 16 terrorism-related cases in the years immediately after the Good Friday Agreement.
However, Ms Villiers said it was impossible to give a total beyond that, because records for the decade leading up to the crucial peace agreement had either been lost or not kept.
The royal prerogative of mercy (RPM), commonly known as a royal pardon, allows changes in sentences without the backing of, or consultation with, Parliament.
Northern Ireland First Minister Peter Robinson has called for the issue of royal pardons to be included in the judge-led inquiry into the On the Runs controversy.
On the Runs is the term used to refer to people who are suspected of, but who have not been charged or convicted of paramilitary offences during the Troubles.
It was a process that involved letters being given to republican paramilitary suspects assuring them that they were not wanted by police anywhere in the UK.
John Downey, from County Donegal in the Republic of Ireland, had denied killing four soldiers in the attack.
A court ruled that he should not be tried because of the assurance contained in a letter that he had been given in error by the government.
Informants who gave evidence during so-called supergrass trials are thought to be among the recipients of the pardons.
However, Theresa Villiers indicated that some names and uses of royal pardons had never been made public.
When royal prerogatives of mercy are used in England they are printed in the London Gazette.
However, RPMs are generally not published when they are granted in Northern Ireland.