Chief Executive Bill Sweeney has said that England's Rugby Football Union (RFU) will lose £107m if this year's autumn internationals are cancelled.
Last year's losing World Cup finalists are due to welcome New Zealand, Argentina, Tonga and Australia to Twickenham this November.
The RFU boss admits that the financial impact of the coronavirus pandemic could be "catastrophic" for the game in England and even if the November Tests went ahead behind closed doors, losses would total £85m.
"It is a very significant loss of revenue and we are doing what we can to mitigate it," Sweeney told the UK government’s Digital, Culture, Media and Sport committee as part of a discussion on the impact of the coronavirus on England's major sports.
The pandemic has already seen the RFU lose £15m this year and even if the matches in November go ahead, the union is still set to lose £32m.
The 2020 Six Nations Championship has yet to be completed and World Rugby guidelines, announced last Monday, state that elite matches should be played behind closed doors until a vaccine is freely available.
"Twickenham is a major asset for us - 85% of our income comes from hosting men’s international games at Twickenham," Sweeney added.
"When you own a stadium it is a major cost and at the same time brings in large revenue.
"If this was to be prolonged and the Six Nations games were impacted, then it would be a catastrophic impact on rugby union in England.
"We would be looking at some very severe situations."
Meanwhile, the IRFU have welcomed the government's Roadmap for Reopening Society and Business, which was revealed on Friday.
The document states that rugby in Ireland can not resume any sooner than 10 August.
The IRFU say they will be discussing the implications of the document with Sport Ireland and the Department of Transport, Tourism and Sport.