Objections lodged against the Garth Brooks’ concerts are believed to have included signatures from people living abroad, children, and a prison inmate.
Gardai investigating claims of bogus complaints about the five shows have established a series of irregularities.
It comes as yet another round of intensive talks were under way last night aimed at salvaging the gigs.
Ticketmaster have delayed the refund process until Thursday, two days after they were originally due to begin giving disappointed fans their money back.
They said that the decision to delay the commencement of refunds is due to ongoing negotiations “to try and find a resolution to the concerts situation”.
The Irish Independent understands that Dublin City Council officials and gardai have been alarmed over some of the identities which are alleged to have submitted applications.
“It's believed that the signatures belong to children, people with intellectual disabilities, people living abroad and a person in the custody of the State – it's suspected that illegal activity has gone on here,” a well-placed source said.
Detectives suspect that between 35pc and 40pc of the almost 400 objections lodged may be forged.
The objections of local residents played a major role in the decision of city manager Owen Keegan to only grant licences for three Garth Brooks’ performances rather than the planned five.
It is now expected that the issue of bogus objections will be considered as part of the latest negotiations between interested bodies.
It's understood that promoter Peter Aiken is attempting to convince Dublin City officials that the revelations surrounding the objections should pave the way for a review on the decision to block five concerts over five consecutive nights.
Tanaiste Joan Burton also reignited hopes for fans, as she said that she believes there is still a “window of opportunity” to get all five of the concerts “over the line”.
Speaking on RTE yesterday morning, Ms Burton also acknowledged that there were strong indications that a number of the objections were bogus and said that it appears that people “were not in fact properly consulted or their names were used without their knowledge”.
Newly appointed Environment Minister Alan Kelly has ruled out implementing emergency legislation to solve the issue surrounding the five Croke Park dates and said that it will serve to make “an already bad situation worse”.
Mr Kelly said that such “rushed legislation” could open up all the concerts to possible legal action, adding that he will “not be going down this road”.
He said he is “legally precluded from intervening in any individual decision made by a planning authority” and that it would be “entirely inappropriate”.
“I believe this situation can only be solved by all the parties coming together in an atmosphere of calm and with all sides being flexible in their approach,” he added.
He said that “a line needs to be drawn under this controversy over the next 48 hours”