An in-depth study also found widespread reports of increased intimidation and violence on the streets.
It said the combined use of prescription drugs and alcohol was causing anti-social behaviour in the city and on the Luas.
The study, Rapid Assessment Research of drug and alcohol-related public nuisance in Dublin city centre, was carried out for the Strategic Response Group.
The group brought together drug treatment centres, homeless agencies, Dublin City Council, the gardaí, and local drug task forces.
The research, conducted by Marie Claire Van Hout and Tim Bingham, examined Garda computer crime records, then “mapped” Dublin for crime levels, and conducted surveys among people on the ground.
Garda records showed 6,663 crimes were detected in the 14 months between Dec 2010 and Jan 2012. Of those records that were filled, 87% were recorded as alcohol-related
The mapping showed the O’Connell St area recorded the most crimes (2,872). Some 44% were property crimes and 35% were public order offences.
The area with the second highest levels of crime was around Temple Bar (1,346), but here public order offences dominated (56%).
The Grafton St area came third (1,053), where property crime dominated (59%).
A detailed examination of the area was also conducted. Of 26 drug users, 81% came into the area daily. Some 42% said they used the Luas, while 38% walked.
The most common drugs used were methadone and zimovane, a prescription sedative, followed by alcohol. Almost all users said they had been arrested or moved on by garda.
Of 25 passers-by surveyed, 40% said they felt unsafe in the area during the day, rising to 60% at night.
Researchers spoke to 23 service users (addicts in treatment), 19 business or transport figures, and 19 community, voluntary, and statutory representatives.
Service users said much of the nuisance and violence was caused by alcohol.
Respondents said the high use of prescribed tablets led to users being disinhibited and noisy.
They said there was more intimidation and violence on the streets, influenced by increased competitiveness among gangs, more people dealing and users hanging around all day. As well as more begging, some agencies reported more street-based sex work by women.
Gangs were using more children and young people to deal, who often used bicycles for mobility and did not fear the authorities.