In a letter from the country star to promoter Peter Aiken, he says: "If you think for any reason that the 'powers that be' in Ireland can fix this, then I will faithfully go to the last second."
The letter begins: "I cannot begin to tell you how badly my heart is breaking right now. I hope you understand that to play for 400,000 people would be a dream, but to tell 160,000 of those people that they are not welcome would be a nightmare.
"To do what the City Manager suggests (play three shows and not all five) means I agree that is how people should be treated and I just can't agree with that."
Brooks continued: "Our guys are still en route and if there is any chance that the five planned concerts can be salvaged and nobody is being let down then we can proceed as planned until the refunds begin.
"If you tell me: 'Garth, thanks but it is over', I will cease my efforts and bring out people and gearback to the States.
"If you think that for any reason that the 'powers that be' in Ireland can fix this, then I will faithfully go to the last second."
He concluded: "Please let me know how to proceed."
The US star had sold 400,000 tickets for the gigs at Croke Park stadium in Dublin later this month.
In January, Brooks announced his return to the venue after 17 years for two gigs, but huge demand for tickets meant three extra dates were added.
However, Dublin City Council would only approve licencing for three of the Croke Park concerts leading Brooks to cancel all the shows. On Tuesday, concert promoters Aiken announced that all five shows would not go ahead.
Brooks said to choose one show over another "would be like asking to choose one child over another".
The Ticketmaster refund information is as follows:
For Ticketmaster tickets purchased over the Phone, Online or Mobile
No action is required if you (the ticket purchaser) purchased tickets by these channels. On Tuesday, 15th July a full refund including service charges will automatically be returned to the card used to make the purchase. Please allow 7-10 working days for the refund to reach your account.
For tickets purchased through Ticketmaster ticket centres
POSTAL: A refund form is available via the Garth Brooks FAQ page at www.ticketmaster.ie/gbrefunds. Please print, complete and return this form along WITH your GARTH BROOKS TICKETS to PO Box 4695, Dublin 2. Please make a note of the show date and your seat details and retain the left hand portion of the refund form for your records. A full refund including service charges will be processed by bank transfer within 21 days of receiving the form and tickets.
IN PERSON AT TICKET CENTRES: From July 15th you may return your tickets to the ticket centre where you purchased them from and complete the refund form which will be available at the ticket centre from this date. The completed form together with your GARTH BROOKS TICKETS should be handed in at the ticket centre. Please make a note of the show date and your seat details and retain the left hand portion of the refund form for your records. A refund by bank transfer will be processed within 21 days of receiving the form and tickets.
Please note: If you purchased tickets from News & Deli Dundalk /Fassaugh Stores Cabra, Dublin /Whites Wexford /the Irish Shop Ennis/ Cusack Park Ennis, these are no longer affiliated with Ticketmaster. Refunds for tickets purchased at these ticket centres are available from any existing Ticketmaster ticket centre using the same refund process as above or alternatively you can use the postal option also set out above.
See www.ticketmaster.ie/gbrefunds for full details.
Mr Keith English, Managing Director, Ticketmaster Ireland, said: "We understand the disappointment of Garth Brooks fans. Having reviewed the huge task at hand, we believe the process we have outlined is the simplest and most efficient for fans. The scale of this operation is unprecedented and therefore we would ask customers to continue to be patient."
In relation to transport refunds, a statement from Translink said: "As we have now been advised by concert promoters that all Garth Brooks concerts scheduled for late July have been cancelled, Translink will be refunding customers who had booked to travel with us to these concerts on our special coach and rail services.
"We will be refunding full monies to the credit/debit card used during the booking process; no further action is required from passengers for this to happen.
"Due to the unprecedented number of refunds involved which require processing and coinciding with the forthcoming July public holidays, we anticipate a 15-20 working day period for all repayments to be completed."