Thousands of people displaced by Tuesday's earthquake remain in shelters across Kumamoto Prefecture, where running water has been cut off in tens of thousands of homes.

Footage recorded on Friday at an evacuation centre inside Yatsushiro Elementary School showed residents collecting relief supplies, resting on the gymnasium floor and relying on bottled water for basic needs.

"The water supply is cut off, which means I can't use the toilet. I can't wash my face or hands with the tap water. That’s why we are using this bottled water," one evacuee said.

Many residents also described the challenges of sleeping in crowded conditions while aftershocks continue.

"There are so many people around, and since the floor is made of boards, my backside hurts, and it's hard to sleep. Also, there were aftershocks about every 15 minutes, so I couldn't sleep. I haven't got a proper night's sleep," another evacuee explained.

Authorities said more than 79,000 households across Kumamoto Prefecture remain without running water, while around 9,000 people are still living in evacuation centres.

With temperatures expected to reach 36C, officials are concerned about the risk of heat-related illnesses as emergency crews continue efforts to restore water and other essential services .

Despite the difficult conditions, some evacuees said they were thankful for the support available at the shelters.

"It wasn't exactly close by, but my child brought me here, since they were in the area. It's a huge help, though, because people bring everything along - tea, bento boxes, and so on," one resident shared.

The earthquake has claimed 34 lives and caused widespread damage to homes, roads and bridges. It also triggered a deadly explosion at a shopping centre, while rescue and relief operations continue across southern Japan .