Ireland's Six Nations match against France in Paris is under growing threat following the French government’s announcement that all "confined" gatherings of more than 5,000 people have been cancelled.
The move comes in response to the coronavirus, which has infected 73 people in France so far.
Andy Farrell's side, whose tie against Italy due to be played next weekend had already been postponed, are scheduled to play Grand Slam-chasing France on 14 March.
The Paris half-marathon, which was due to take place tomorrow, has been cancelled, as was the final day of an annual farm show.
"All public gatherings of more than 5,000 people in a confined space are temporarily banned across France," said health minister Olivier Veran.
However, the definition of "confined" has not been clarified and today's five Top14 games across the country have not been affected, while there is also a full programme of games in the top French football division, Ligue 1, this weekend.
Six Nations organisers said during the week that "all other matches are currently scheduled to go ahead as normal. We will continue to monitor the situation very closely with all Unions and the respective Government authorities and health organisations".
The IRFU and the Six Nations have been contacted for comment.
World Rugby are due to hold a meeting in Paris on Monday and no update is expected ahead of that.
Asked about the possibility of the France match going ahead yesterday, Farrell said: "We don't know, that's the answer, we don't know. All we can do is prepare properly that the game is going ahead.
"We've been in for a few days this week and that was the normal prep that we was going to have anyway.
"We're going to have a rest this weekend, come back in Sunday and train Monday and Tuesday, then Thursday.
"Then we have a long weekend off, so the key for us is to use the time appropriately and to our advantage as well."