People will have to buy tickets to go to nightclubs and late-night venues, under new guidelines published this evening.
Culture and Arts Minister Catherine Martin says regulations for this will be in place next week.
Officials say the rule is in place to "facilitate contact tracing".
The guidelines state tickets must be "secured in advance", with venues allowed to hold 'ticketed events only'.
Clubs can reopen without the ticketing rule this weekend.
The news comes just hours before the sector opens tonight for the first time in nine months.
Full capacity is allowed at nightclubs, and 1,500 standing customers can go to live music events.
Announcing the measures, Minister Martin said: said “The safe and viable return of the night time economy has been greatly anticipated, and welcomed, by the businesses and thousands of staff who bring Ireland’s cultural and nightlife economy to life.
"COVID is still a real threat to our society and the safety guidelines are necessary to balance public health while also facilitating the reopening of all sectors.
"Night club and live entertainment venues can return to welcoming customers (subject to capacity and standing limits for live events), however, it is vitally important that each venue operator utilises their skilled health and safety expertise, and exercises judgement and caution with due regard to protecting public health.”
The measures will be reviewed in three weeks.
Reacting to the news, the Vinters' Federation of Ireland says the guidelines will be "impossible to implement".
Padraig Cribben, VFI Chief Executive, said: "Yesterday it was suggested events would be all ticket only for that stipulation to be removed from the guidelines, yet hours before clubs reopen tickets will once again be mandatory.
“This really has been a shambolic process from the press conference last Tuesday to this last minute senseless U-turn.
"We now have a situation where clubs can sell tickets at the door this weekend but must move to ticket only in advance by next week.
“We’re extremely worried the new guidelines will lead to public order incidents as ticketless groups gather outside clubs. It is unworkable."
The delay in publishing the final reopening guidelines meant one popular Dublin club - Krystle - scrapped its plans to reopen this weekend.