Norwegian energy company Equinor has submitted a bid to develop an offshore wind farm together with other companies in the latest round of Japan's state auctions, two sources said, as it seeks a foothold in the fledgling market.

Equinor's bid underscores the focus some wind players are putting on Japan even as they scale back elsewhere, despite some international players' frustration with strict bidding rules and an earlier auction round having been won by Japanese companies.

A latecomer to offshore wind, Japan wants to build up to 45 gigawatts (GW) of capacity by 2040 from less than 1GW now, which would make it a top-five offshore wind market.