The 360 km interconnection, currently the world’s longest such link, has been repeatedly delayed, most recently after electrical equipment was damaged in rough seas during transport from Germany.

Its completion will allow Hydro Tasmania to enter the national electricity market, using its abundant hydro resources to bolster the mainland’s peak summer demand.

Hydro Tasmania chief executive Geoff Willis said: “I congratulate Basslink’s owner, National Grid, for achieving this project of national significance. Basslink went through the most rigorous approval process for any major energy project in Australia’s history.”

An official opening ceremony for Basslink is planned for mid-May.