Cardinal Sean Brady said the relatives of those still missing deserved closure. Seventeen people were murdered and secretly buried by republican paramilitaries during the conflict.
Fourteen years ago the British and Irish governments set up an independent commission to help locate the bodies. While the majority have been found, seven victims remain unaccounted for.
The work of the commission continues, but it requires confidential information from those with knowledge of the crimes.
Cardinal Brady made his appeal after the annual Easter week memorial service for the families of the Disappeared in St Patrick's Cathedral in Armagh.
"The death of a loved one is always a heartbreaking time for those left behind, but when your loved one is taken away as these victims were without any trace, the pain is almost too much to bear," he said.
"Every person is entitled to a full Christian burial, and every family is entitled to closure and be thankful that their loved has finally been laid to rest. So this Easter I would appeal to anyone who may have any information - no matter how small or insignificant they think it is - to contact the Independent Commission for the Location of Victims Remains.
"Without your help, the remaining families will continue to suffer unnecessary pain."
Following the Service, co-commissioner Frank Murray pledged that every possible lead and fresh piece of information would be investigated by a dedicated team.
He said: "This is important for families who want to give a Christian burial and bring them the peace of laying their loved ones to rest. We hope that Cardinal Brady's appeal will strike a cord with those who hold any information."
The Disappeared confidential international telephone free
phone number is 00800 555 85500.
The PO Box address is ICLVR, PO Box
10827, Dublin 2.
No information received by the commission can be used
for criminal investigation purposes.