British Olympic Association chairman Hugh Robertson says it is unthinkable that this summer's Tokyo Games will not get postponed due to the coronavirus pandemic.
The BOA will join the growing calls for the Games, due to start on July 24, to be delayed, with Canada and Australia already saying they will not send a team to Japan.
The BOA, the British Paralympic Association and funding body UK Sport will hold a conference call on Tuesday afternoon with bosses from the summer Olympic and Paralympic sports to finalise the decision.
An official announcement from Tokyo 2020 could come on Monday as the executive board is meeting and then holding a press conference afterwards.
Robertson told the Today programme on BBC Radio 4: "We are pretty much there, I think a postponement is pretty much inevitable.
"The final piece with the jigsaw is that we have telephone call this afternoon with UK Sport, the British Paralympic Association, our sports' and athletes' representatives, just to absolutely nail this down.
"I really don't see how there is any way the IOC can press ahead with a start in July this year. We have always said there were two things that for us were really important here.
"The first was preserving the competitive integrity of the Olympic Games when the countries are effectively in lockdown and athletes can't train and some of them may catch the coronavirus, there is no way you can preserve that competitive integrity.
"Secondly there is a really serious question about whether it would be appropriate to hold an Olympic Games against this backdrop.
"For both of those reasons, it is my personal view, that July is a total non-starter, but we just need to do that final bit of consultation."
International Olympic Committee member Dick Pound had said the organisation has already decided to postpone the showpiece event.
"On the basis of the information the IOC has, postponement has been decided," Pound told USA Today.
"The parameters going forward have not been determined, but the Games are not going to start on July 24, that much I know."
The Canadian Olympic and Paralympic committees have announced they will not compete in Tokyo this summer, while the Australians have told their athletes to prepare for a postponement to the summer of 2021.
Team USA said it had surveyed its athletes with nearly 93 per cent of the 1,780 respondents preferring to see the Games postponed rather than outright cancelled, while 68 per cent said the event could not be fairly competed if continued as scheduled.
The Germany Olympic Committee said a postponement announcement was "long overdue".
A statement read: "The examination of the relocation is a correct step of the IOC, which is long overdue in view of the current global health situation, because this now clearly signals internally and externally that the implementation of the Games is clearly subordinate to world health."
This season's European Champions Cup and Challenge Cup semi-finals and finals have also been postponed.
Tournament organisers European Professional Club Rugby reconfirmed the suspension of this season's tournaments.
Quarter-finals next month had already been postponed, but now the semis from May 1-3 and finals in Marseille on May 22-23 have followed suit.
EPCR, though, says it is committed to completing the Champions Cup and Challenge Cup campaigns.
