TOKYO, July 2 (Xinhua) -- Japan's main southwestern island of Kyushu, along with neighboring regions are being hit by torrential rains, the weather agency here said Tuesday, with evacuation advisories issued due to the severity of conditions.

Around 850,000 people were urged to evacuate from nearly 400,000 homes in the hardest-hit regions across Kagoshima, Kumamoto and Ehime prefectures, local media reported.

The evacuation advisory issued was level four, the second-highest on the weather agency's scale which peaks at five.

Based on this, local officials said those under advisement should move to emergency shelters for safety.

According to Japan's Meteorological Agency (JMA), the torrential conditions are being created by a seasonal rain front lingering over the area in Japan's southwest, creating storm clouds by the warm and damp air the front is creating.

Parts of the Kyushu region have been inundated with more than 700 millimeters of rain since the torrential downpours began, with the weather agency warning that thunderstorms and intense torrential rain could lead to an increasing risk of mudslides.

Warnings have also been issued for people to be vigilant for possible lightening strikes as well as tornadoes.

The JMA said the front could become even more active and affect other regions through Friday of western Japan as the system lingers and brings more periodic, heavy downpours.

Before midday on Wednesday through Thursday this week, the JMA said it expects more than 80 millimeters of rain per hour in some parts of Kyushu and neighboring regions, which far exceeds the average rainfall for the entire month of July in a single day.

In northern and southern Kyushu in the 24 hours to noon on Wednesday, weather officials said that up to 150 millimeters of rain is expected.

Advisories have been given for people in inundated areas to be aware of the potential for heavy flooding, especially in low-lying areas and near rivers that might burst their banks. People have also been put on high alert for mudslides.

On Tuesday, a slope in a residential area of Nagasaki City collapsed due to the adverse weather conditions, but according to the firefighter in Nagasaki Prefecture, no reports of injury or damage to infrastructure have been reported as yet.