International energy companies, from Germany's RWE to Spain's Iberdrola, are urging Japan to beef up offshore wind power auctions and make investments more attractive, amid soaring installation costs as competition for suppliers grows worldwide.

Although desperate to ease its heavy dependence on energy imports from the Middle East and Russia, Japan is late to offshore wind, but some industry players say it is taking a more cautious approach that puts it at a disadvantage.

"It's a global race and we can't look at it in isolation," Jens Orfelt, president for offshore wind development for Asia-Pacific at RWE Renewables, told a recent conference.