A decision on whether Covid passes are needed to enter to pubs and restaurants will be made at the "last minute", First Minister Mark Drakeford has said.
Ministers will consider whether to expand the scheme at the next Covid rules review due on Friday.
Covid passes are already required for cinemas, theatres, nightclubs and large events in Wales.
The Welsh Government said the case is in the Cardiff and Vale University Health Board area and is linked to international travel.
The First Minister told BBC Politics Wales he did not think the Welsh government would be considering extending passes to hospitality if it had only been dealing with the dominant Delta variant.
He said: "If we were to do it, it would simply be to help those businesses to stay open and still attracting customers through the door because people would feel confident that everybody else in that setting were either vaccinated or had taken a lateral flow test."
"But we haven't made that decision, and we won't make that decision right up until the day we have to, because circumstances and knowledge are developing so fast around the new variant that you ought to wait to have the maximum amount of information that you can."
Meanwhile, the Welsh government have followed the UK government in reintroducing a 48-hour Pre Departure Test requirement for all travellers.
This means that travellers will need to have a negative PCR or Lateral flow test as close as possible to their departure time before they can travel.
The new testing measures will come into force on Tuesday.
From 4am on Monday, Nigeria will join the following countries on the red list:
Currently, anyone entering the UK from a country which is not on the red list must self-isolate and take a PCR test on or before day two of their arrival in the country, and can only leave their quarantine when they receive a negative result.
However, if a country is on the red list, only UK and Irish residents are allowed to travel from it into the country and they must quarantine in a government-approved hotel for 10 days at their own cost. Non-UK and Irish residents who have been in a red list country in the past 10 days are not permitted to enter the UK.