Japan would be weakened economically and strategically, and Australia’s reputation as a reliable energy supplier would be shattered, if export gas was redirected to the domestic market as the Greens are demanding, Tokyo’s former top envoy to Canberra says.

Shingo Yamagami, who spoke out against “energy nationalism” during his tenure as Japanese ambassador between 2020 and 2023, said he was alarmed at growing calls by the Greens for Australia to breach gas export contracts rather than develop new gas fields to meet domestic demand.