Organisers of the Closing mass of the World Meeting of Families in Phoenix Park have said that the infrastructure in Dublin cannot cater for all people who have indicated that they are planning to travel to the event by car.
Pope Francis is due to attend the event on 26 August, as well as the Festival of Families, which is being held the day before in Croke Park.
Organisers of the Phoenix Park mass, which is a ticketed event, say that tickets will now be issued ten days later than planned.
This is in order to help people plan their journeys in the most effective way, and to encourage them to use public transport.
The mass is expected to be one of the biggest events in Ireland this year, with a capacity of 500,000 at the Papal Cross.
Organisers say people will get their print at home tickets via email in plenty of time for the mass.
30,000 people have registered to attend the Pastoral Congress of the World Meeting of Families, which runs in the RDS in the days before the pope's visit.
This will be the highest attendance ever at the World Meeting of Families congress since it was established 24 years ago by Pope John Paul II.
The World Meeting of Families takes place every three years and the event in Dublin will be the second that Pope Francis has attended during his papacy.