* Japan still assessing damage, loss of life
* Dozens believed trapped in rubble after quake
* Cost of damage could run to several billion dollars
* No irregularities reported at nuclear plants
* Sony, Toyota, Nissan operations affected
By Minami Funakoshi and Kiyoshi Takenaka
TOKYO, April 17 (Reuters) - Japanese authorities have ordered nearly a quarter of a million people from their homes after a deadly earthquake struck a southern island and the search for survivors went on into the early hours of Sunday amid worsening weather conditions.
A 7.3 magnitude tremor struck early on Saturday morning, killing at least 32 people, injuring about a thousand more and causing widespread damage to houses, roads and bridges.
It was the second major quake to hit Kumamoto province on the island of Kyushu in just over 24 hours. The first, late on Thursday, killed nine people.
Heavy rain and wind were forecast overnight, with temperatures expected to drop to 13 degrees Celsius (55 degrees Fahrenheit). Firefighters handed out tarpaulins to residents so they could cover damaged roofs.
"The wind is expected to pick up and rain will likely get heavier," Prime Minister Shinzo Abe told a government meeting. "Rescue operations at night will be extremely difficult ... It's a race against time."
Television footage throughout Saturday showed fires, power outages, collapsed bridges, a severed road hanging over a ravine and gaping holes in the earth. Residents near a dam were told to leave because of fears it might crumble, said broadcaster NHK.
"I felt strong shaking at first, then I was thrown about like I was in a washing machine," said a Tokai University student who remains isolated in the village of Minamiaso.
About 422,000 households were without water and 100,000 without electricity, the government said.
NHK said around 240,000 people had received evacuation orders across the affected region amid fears of landslides. Some shelters were too crowded to admit any more people, it said.
Troops set up tents for evacuees and water trucks were being sent to the area. Around 25,000 extra soldiers were due to arrive, as well as more police, firefighters and medics.
The National Police Agency said 32 people had been confirmed dead. The government said about 190 of those injured were in a serious condition.
Chief Cabinet Secretary Yoshihide Suga said nearly 80 people were believed trapped or buried in rubble. Rescuers pulled 10 students out of a collapsed university apartment in the town of Minami on Saturday.
"RING OF FIRE"
Japan is on the seismically active "ring of fire" around the Pacific Ocean and has building codes aimed at helping structures withstand earthquakes.