The Presbyterian Church in Ireland welcomed Gen de Chastelain's statement on decommissioning but said the IRA must act on its promises.
In a statement issued yesterday afternoon by its church and government committee, the church said Gen de Chastelain's statement would be significant only if it led to immediate action.
"The statement issued today by Gen de Chastelain saying that he believes the proposal put forward by the IRA will initiate a process that will put their arms completely and verifiably beyond use is only significant if it leads immediately to action," said the committee.
The statement questioned the future intentions of the British and Irish governments in the event of the IRA failing to deliver.
"The question remains about what the two governments intend to do if no satisfaction is given to the International Commission on Decommissioning. This issue is of concern to people in both parts of Ireland. The committee reiterates its belief that the decommissioning of weapons by all paramilitary groups is a moral and political necessity."
The committee noted the "increasing sense of uncertainty in the community which contrasts sharply with the confidence and hopefulness which followed from the Belfast Agreement." The Presbyterian Church is the largest Protestant denomination in the North.
"The committee believes that if the Northern Ireland Assembly ceases to function it will not be to the advantage of the people of Northern Ireland who would be deprived of representation by locally elected people at this level, as well as knowledgeable and accessible locally appointed ministers," said the statement.
Condemning widespread loyalist and republican violence over recent weeks, the Presbyterian Church took the opportunity to condemn last week's killing of Mr Gavin Brett outside a GAA club in north Belfast. The statement described the murder as "an outrageous act".