Japan Rugby Football Union chairman Shigetaka Mori says the Sunwolves' 2020 season is over, with Rugby Australia (RA) confirming the Tokyo-based team will not be involved in its domestic competition.
With rugby preparing to return from the coronavirus shutdown, the Sunwolves had been in talks to join Australia's four Super Rugby teams and Perth-based side Western Force in a 12-week tournament slated for July-September.
However, RA says travel curbs and logistical difficulties due to coronavirus have made it too hard to involve the Sunwolves, who face an uncertain future having already been axed from Super Rugby after the current season.
Super Rugby's governing body SANZAAR has not officially abandoned the 2020 season but Mori said the Sunwolves would not be playing again this year.
"The Sunwolves, loved by many fans, have reached the end of the 2020 season," Mori said in a statement, thanking the fans, players and staff for their dedication.
"The five-year trajectory of Sunwolves will never disappear.
"When the Japan national team's success in the Rugby World Cup last year was talked about, it proved to many fans that the existence of the Sunwolves was a key factor behind this.
"Going forward, we will continue to make use of the experience gained by the existence of the Sunwolves to work with fans and other stakeholders to further develop Japan Rugby."
Sunwolves chief executive Yuji Watase added: "It is extremely unfortunate and disappointing but the reality is that the Sunwolves' time in Super Rugby has come to an end for now.
"It has been an honour and privilege for us to be part of the toughest rugby competition in the world."
RA's interim chief executive Rob Clarke said in a statement the Sunwolves' participation in the Australian competition would have been "severely compromised" by a lack of preparation time available for the team.
Australia's 'Super Rugby AU' competition is scheduled to start July 3, pending sign-off from broadcasters.