Six Nations organisers are working on contingency plans to hold a second tournament later in the year, The Rugby Paper has reported.
The unions of England, Wales, Ireland, France, Italy and Scotland are holding talks this week, with one of the many potential scenarios under discussion a full 15-match, eight-week tournament to be held in October and November.
The report said plans for the tournament were being drawn up amid concerns that the COVID-19 pandemic would prevent New Zealand, Australia, South Africa and Argentina from touring Europe in November.
"Some people will no doubt throw their hands up in the air and accuse us of devaluing the tournament, but what do they expect us to do?" The Rugby Paper quoted an official as saying.
"In such exceptional circumstances we would be failing in our duty to the game as a whole if we didn't have a contingency plan."
Rugby, like virtually all sport around the world, has been hit hard by the new coronavirus outbreak. This year's Six Nations saw four matches postponed.
The sport's governing body World Rugby has already created a relief fund of around $100 million to assist unions as they grapple with the financial impact of the pandemic.
The report added that an unprecedented second Six Nations event this year had the potential to generate more than 100 million pounds ($123.31 million) in ticket sales.
Reuters