Irish living abroad will have to accept the "difficult" reality that it is now "unlikely" they will be able to fly home for Christmas, the Sinn Féin leader has said.
Mary Lou McDonald said international travel will be "problematic" as it is not only dependent on Covid levels here but also the rate of the virus in other countries.
It comes as Tánaiste Leo Varadkar warned people not to book flights home for Christmas claiming it is "too soon" to do so.
Ms McDonald said: "I think certainly, it's too early for people to make definite plans, but I think it is most unlikely that lots of people will be able to travel home. As and when the public health advice is issued we'd be saying to people just to follow that advice as difficult as it is to respect that advice.
"Families up and down the country, including my in my own I should say, have been talking about this issue of Christmas and travelling home and it's a tradition for all of us, that your people come home, but this year is different."
She added: "We'll come out of level 5 on December 1st and that will naturally trigger, I hope, a very comprehensive assessment of where we're at, I hope we will be in a much stronger and a much better place but I absolutely accept that the issue of international travel will still be problematic."
However, she said there will be "exceptional circumstances" for some, where on a "compassionate basis" people would have to travel home.
"Where there is a very particular crisis or trauma or anxiety or difficulty in a family I think there has to be some level of compassion and some level of flexibility built-in."
Calling for an all-island approach to Covid, Ms McDonald said: "We can't have a reservoir of this disease anywhere on the island, if it's on the island it imperils all of us."
It comes as Sinn Féin voted against a plan to extend restrictions in Northern Ireland for a week, as they sided with the chief medical officer who advised that a longer lockdown was required.
Hitting out at Arlene Foster's party which had pushed for an easing of restrictions, Ms McDonald said: "The idea that the DUP can turn public health and our need to keep all of us safe and to do the right thing for everyone in very difficult circumstances, that they can turn that into an orange versus green, them versus us issue is really very very shocking but that's what happened.
"The idea that you would be lifting restrictions at a time where we're just not on top of things is wrong, is dangerous and the CMO was very blunt in the advice that he gave to the Executive," she told RTÉ's Today with Claire Byrne programme.
