* May steel exports at 9.42 mln T, up 3.7 pct vs April
* Jan-May steel exports up 6.4 pct to 46.28 mln T
* Iron ore imports in May highest since December (Adds comment, iron ore milestone)
SHANGHAI, June 8 (Reuters) - Chinese steel exports rose 3.7 percent to 9.42 million tonnes in May from the previous month, customs data showed on Wednesday, as steel mills continued to ship output abroad in sales that have raised global trade tensions.
China also boosted its iron ore imports by 3.4 percent in May to 86.75 million tonnes from the previous month, the highest since December. Shipments climbed 9.1 percent to 412.15 million tonnes in the first five months of the year, customs data showed.
Chinese steel mills accelerated production amid a seasonal pick-up in demand and higher prices, boosting appetite for the steelmaking ingredient, with imports staying above 80 million tonnes a month this year apart from the holiday season of February.
Total steel exports rose 6.4 percent to 46.28 million tonnes in the first five months of the year, according to data from the General Administration of Customs. TRADE/CN
China's robust exports have come under fire from global rivals, who have accused it of dumping cheap exports after a slowdown in demand at home.
"The pushback to steel exports has been more from the U.S. and Europe which only represent less than 10 percent of total exports," said Daniel Hynes, commodity strategist at ANZ.
"We're still seeing strong exports to the rest of Southeast Asia and obviously the Chinese mills have a competitive advantage into this region," said Hynes, who sees China's total shipments again topping 100 million tonnes this year.
China's steel exports reached a record 112 million tonnes in 2015.
South Korea is the top market for Chinese steel, with shipments reaching 13.5 million tonnes last year, compared with 2.35 million tonnes to the United States, according to data compiled by MEPS consultancy. trade dispute over steel escalated after the U.S. regulators launched on investigation into complaints by United States Steel Corp X.N that Chinese competitors stole its secrets and fixed prices. SRBcv1 surged 80 percent in late April from decades-low prices hit in December last year, prompting steel mills to ramp up production and some zombie mills to resume output, complicating government efforts to cut overcapacity.
China has committed to curbing its steel capacity and winding down weak state enterprises by taking new measures and strengthening global coordination.