The Heineken Champions Cup and the Challenge Cup have been temporarily suspended due to COVID-19, the European Professional Club Rugby has confirmed.
Irish provinces Leinster, Munster and Connacht are competing in the Champions Cup.
Two rounds of fixtures, which were scheduled for the weekends of January 15-17 and 22-24, have been postponed in response to the new strain of the virus.
The decision was taken after a meeting between the EPCR, the Ligue Nationale de Rugby and representatives of the French ministries of the Interior, Health and Sport.
French clubs had earlier been advised by the French government to avoid cross-border matches.
"Following a directive from the French authorities that the participation of Top 14 clubs in the Heineken Champions Cup and Challenge Cup at the current time constitutes too great a public health risk, EPCR has no choice but to announce today that the 2020/21 tournaments are temporarily suspended," the EPCR statement read
"EPCR and the Ligue Nationale de Rugby took part in a meeting by audio conference last week with representatives of the French ministries of the Interior, Health and Sport, as well as of the President's office.
"Notable updates to EPCR's Covid-19 protocols were presented to the French authorities, including the addition of PCR tests no earlier than three days before matches in the tournaments, conforming to French government guidelines and supplementing the existing, meticulous contact tracing measures put in place with a view to limiting the risk of transmission.
"Against the backdrop of the recent detection of a new strain of coronavirus, the French government has directed that French clubs postpone their participation in EPCR’s tournaments for the month of January, both for matches scheduled in France and for those due to be played in the United Kingdom and Ireland.
"On the basis of this directive, EPCR had no choice but to temporarily suspend the pool stage of the Heineken Champions Cup and the preliminary stage of the Challenge Cup."
The 2021 Women's Six Nations has already been postponed.
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