The family of Robert McCartney claims members of Sinn Fein's paramilitary wing, the Irish Republican Army (IRA), were responsible for his murder after a bar brawl and that the IRA destroyed evidence and intimidated witnesses.
Party president Gerry Adams said on Thursday that the McCartneys had provided him with a list of names of those they allege were involved.
When he was informed seven of those on the list were party members they were suspended without prejudice pending the outcome of the legal process.
"If any of these seven are found to have been involved in the events surrounding the death of Robert McCartney, or if they do not provide truthful accounts at this time as the McCartney family have requested, Sinn Fein will take further internal disciplinary action to expel these individuals," Adams said.
Catholic support urged
The suspensions come as one of Ireland's most senior Roman Catholic clerics strongly urged his followers to give their support to the police and the legal system in Northern Ireland.
Sean Brady, Primate of All Ireland and Archbishop of Armagh, also called for anyone who has information about the murder to contact the authorities to help secure a court conviction.
"If any of these seven are found to have been involved in the events surrounding the death of Robert McCartney ... Sinn Fein will take further internal disciplinary action to expel these individuals"
Sinn Fein leader
"I appeal to them, for the sake of their conscience and in the name of freedom and justice, to do so and to do so urgently," he said.
The IRA has expelled three members as a result of the murder but Sinn Fein has been reluctant to urge supporters to contact the police.
Brady said it was time for Northern Ireland's Catholics to set aside their historic reservations about the police and, "to assume their full civic responsibility for an agreed and representative system of law and order".