Sumitomo Metal Industries Ltd., Japan's third-largest steelmaker, posted a wider-than-expected quarterly loss after last month's record earthquake damaged its biggest plant.

Net loss was ¥42 billion for the fiscal fourth quarter that ended March 31, the first loss in five quarters. That compares with a profit of ¥7.7 billion a year earlier, and is bigger than the ¥9.9 billion loss forecast derived from its Jan. 28 estimate for the full-year. Sales fell 1.2 percent to ¥357 billion in the quarter.

Sumitomo will spend about ¥100 billion to bring production at the Kashima plant, which produces more than half of Sumitomo Metal's crude steel, back to "usual levels" by the end of next month, it said Thursday. The plant slashed output to 40 percent of the year-ago level in April and was the hardest hit among major Japanese steel mills after the magnitude 9.0 earthquake and tsunami struck Tohoku on March 11.

The company, which is planning to merge with Nippon Steel Corp., booked a ¥62 billion charge related to the earthquake last quarter and expects to take another ¥15 billion charge this fiscal year, it said.

The steelmaker had a full-year loss of ¥7.14 billion, missing its target to return to a profit. Sales totaled ¥1.4 trillion for the year that ended March 31, 9.1 percent higher than the previous year and 2.6 percent lower than its earlier estimate.