Imagine a headline splashing out news of tourists being killed by a fire at an illegal short-term lodging facility during the Group of 20 leaders' summit in Japan.

That is exactly what Osaka, which is hosting the international event in June 2019, desperately wants to avoid.

Cracking down on the illegal facilities, which can lack sufficient fire and safety measures but are popular with frugal tourists, is at the top of the city's to-do list as an influx of participants before and during the G-20 summit could push other visitors who would ordinarily stay at luxury and business hotels into minpaku, Japan's version of Airbnb lodging.