The organizers of this summer's Tokyo Olympics must decide whether to go ahead with the games after scrutinizing the impact they may have on the nation's medical system, the country's top government COVID-19 adviser said Friday.

The remarks by Shigeru Omi, an infectious disease expert who heads a government subcommittee on the coronavirus, came as another wave of infections, driven by mutated variants, has caused a shortage of hospital beds and medical staff in some areas under a state of emergency.

While addressing a question from an opposition lawmaker in a parliamentary committee, he said it is the "responsibility" of the organizers to determine if Japan can actually host the Olympics and Paralympics, adding, "The decision cannot be made at the last minute."