He said it would be "a terrible tragedy" if the achievements of the past months were eroded by marching rows.
Mr Ahern issued the warning as he met residents from nationalist areas of Northern Ireland seen as potential trouble flashpoints for the summertime season of marches by the Orange Order and other loyalist organizations.
The Irish premier told representatives from Belfast's Ormeau Road and the Garvaghy Road, in Portadown, Co Armagh, that compromise was essential
The aim must be to avoid generating new problems for the Northern Ireland peace deal. He said if the two sides could be persuaded to move from their present positions and agree to talk, progress could be made on the most controversial of the scheduled marches.
Mr Ahern reported: "I think it is entirely reasonable that there should be compromises. There are about a dozen contentious marches out of the hundreds that are really difficult.
"If there were compromise - a two-way process - we could make progress."
The Ormeau and Garvaghy roads residents' associations - who also met opposition leaders in Dublin today - pressed Mr Ahern to take action to avoid trouble during the July marching season. They alleged the Orange Order was attempting to be selective about who they met on the nationalist side.
Garvaghy Road spokesman Brendan MacCionnaith said they had appealed to the Irish government to ensure their communities would not be "subjected to further abuse this year".