Carroll, who is currently on a season-long loan at West Ham from Liverpool and facing an eight-week lay-off due to a knee injury, was with team-mates in Dublin for a weekend Christmas party after the Hammers beat Chelsea 3-1 on Saturday.
Carroll, 23, denies any wrongdoing.
A spokesman for the Garda press office in Dublin said officers received a report of an incident at 2.30am on Monday.
A press photographer claimed he had been assaulted in the capital's main shopping district, Grafton Street.
Officers at the city's Pearse Street station are investigating the incident, which press in Britain and Ireland reported as taking place outside a nightclub.
It is understood members of the West Ham football team were spoken to by gardai following reports of the assault.
No arrests were made, the Garda spokesman said.
Carroll had a history of drink-related altercations during his time at Newcastle, but he has largely avoided trouble since joining Liverpool in a £35 million deal in January 2011.
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