Keith Mills told BBC radio that the delayed Olympics, scheduled for July-August, were looking unlikely to happen in his opinion due to the COVID-19 pandemic.
"If I was sitting in the shoes of the organising committee in Tokyo, and thankfully I'm not, I would be making plans for a cancellation," he said.
"I'm sure they have plans for a cancellation but I think they will leave it to absolutely the last minute in case the situation improves dramatically and in case the vaccines roll out faster.
"It's a tough call and I wouldn't like to be in their shoes."