People buying tickets for concerts next summer should be aware they will not be entitled to refunds if the events are rescheduled.
Tánaiste Leo Varadkar said there was "no guarantee" such events would go ahead and that it may be "some time yet" before mass gatherings are allowed.
The music festival Longitude has announced its return in July 2021, an event that typically attracts 40,000 people.
Labour leader Alan Kelly asked the Tánaiste what advice he would give to event companies in relation to such events going ahead during Leaders' Questions in the Dáil.
Mr Varadkar told the Dáil: "There are now tickets on sale for some major events that we all hope will go ahead next summer.
"The advice I would say is that there is no guarantee that those events will go ahead. It might be some time yet before we can attend matches, concerts and mass gatherings. I hope it is possible in the summer, but that's far from sure at this point.
"Under the law it is possible for companies organising those events to cancel them and reschedule them. They don’t have to refund the cost of the ticket, they can reschedule them.
"I think people who are buying a ticket should be aware of that. They’re not guaranteed a refund. They might find the gig rescheduled."
In response to Mr Varadker's comments, MCD Productions said in a statement: "MCD will continue our policy of offering customers the option of a full refund should a show be rescheduled due to COVID-19.
This refund policy applies to all events scheduled to take place in 2020 and 2021, including Longitude and Electric Picnic."
Mr Kelly also questioned the Tánaiste on plans for the rollout of a vaccine, which is expected to begin in January.
Mr Varadkar said the issue of who will be prioritised to receive the vaccine will not be decided by the taskforce chaired by Professor Brian MacCraith, which is due to report to Government on 11 December.
Instead, it will fall to the National Immunisation Advisory Committee (NIAC), Mr Varadkar said.
He added: "We would expect a report from them very soon, as to what the order of prioritisation will be.
"I don’t think it’s going to be rocket science. I think everyone understands that those who will be prioritised will be those who need it the most."
Mr Varadkar confirmed that there will be no charge for the vaccine, which will be paid for through taxation.