GARDAI refused to put an official mark on the numbers that attended mass at the Phoenix Park – because the crowd lagged far behind the expected 500,000.
Both An Garda Síochána and the Office of Public Works (OWP) confirmed numbers were less than expected.
However, they said they did not have the information to confirm the exact turnout.
It has been suggested that the figure was between 150,000 and 200,000.
No tickets were scanned, so it was not possible to calculate exactly how many participants there were.
An estimated half a million pilgrims were gathered to hear Pope Francis hear Mass on the second day of his visit.
Tickets were distributed in July, but the number of people present was probably closer to less than half that number.
The Phoenix Park event took place after Francis visited the Knock Sanctuary in Co Mayo, of which an estimated 45,000 people had come out.
The Sunday saw enormous amounts of rain from the early morning hours, which resulted in a huge hollowing of the park, with pilgrims forced to pull through the blowing storms and constant downpour for a large part of the 3 km walk.
Some reported that, although they had secured their tickets for the event, the amount of walking from the entrance to the park to their standing position prevented them from going, especially for the elderly or sick.
Many also noted that during the papal tour through the center of Dublin via Popemobile the crowds were considerably smaller than expected.
In areas such as College Green, only one or two people were deep, while some streets barely had spectators when the pope passed by.
Meanwhile, the Phoenix Park reopened to the public yesterday at 4 pm, 15 hours earlier than planned after an extensive night clearance.
More than 200 waste collectors worked all night to clean up all public routes. The gates have been put back in place, as well as traffic signs. Tar on the road beams installed for universal access has been removed. The papal site itself has been almost completely cleaned.
Chief Parks Superintendent at the OPW Margaret Gormley said that there was no waste policy for yesterday's event and added that those present were extremely compliant in disposing of their waste in recycling bins throughout the site.
"Given the weather conditions, the volume of people, the infrastructure, I am pleased to say that the park is in a remarkably good condition and is now open to the public again," she said.