* Tighter supply in Australia to support coking coal prices
* Strong steel demand expected to continue worldwide in 2018
* No need to take action in wake of Japan data scandal
TOKYO, Dec 7 (Reuters) - Nippon Steel & Sumitomo Metal Corp , Japan's biggest steelmaker, expects coking coal to stay above $200 a tonne through the January-March quarter amid lower supplies from Australia, which may drag on its earnings.
Australian premium coking coal futures in Singapore have surged nearly 30 percent from a November low of $174 to above $220 a tonne in the first few days of December.
"The recent jump reflected tighter supplies in Australia," Toshiharu Sakae, Nippon Steel's executive vice president, told Reuters in an interview earlier this week.
Slower output at some Australian mines following cyclones earlier this year and renewal works of some loading facilities at a Queensland port lent support to the prices, Sakae said.
Demand from other steel-producing countries is also supporting prices, he said, and some buyers are stepping up purchases from spot market to build inventories ahead of the rainy season in Australia.
"Demand is not particularly heavy in China as it is going through a seasonal output cut, but demand in India is growing gradually," he said.
And while higher raw material costs would hurt the steelmaker's earnings, solid demand for steel products at home and abroad could offset such expenses, he said.
"I think steel demand will stay solid worldwide through next financial year," Sakae said.
Amid Japan's growing data tampering scandal, Nippon Steel wants to reinforce quality audit systems for its subsidiaries as part of its group-wide efforts to ensure quality assurance, he said, without elaborating.
"We don't have to take any fresh actions hastily as we have been making steady efforts in quality assurance," Sakae said.
Tohoku Electric Power Co was the latest Japanese corporation to say it had uncovered cases of data tampering, broadening the scandal that was kicked off in October by Nippon Steel's smaller rival Kobe Steel Ltd.
Kobe Steel has admitted that about 500 of its customers have received products with falsified specifications, part of the fallout from one of Japan's biggest industrial scandals.
Kobe Steel and the data scandal aside, Japan's steelmakers are enjoying the best market conditions in at least three years as steel prices rise with construction in full swing for the 2020 Olympics in Tokyo and automakers boosting production.
Nippon Steel, the world's fourth-largest steelmaker, is projecting a recurring profit of 300 billion yen ($2.7 billion) for the current financial year to March 2018, up 72 percent from the previous year.
($1 = 112.06 yen) (Reporting by Yuka Obayashi and Kentaro Hamada; Editing by Tom Hogue)