Labor has been given compelling market evidence that shows now-scuttled multi-decade east coast supply deals were on the cusp of being struck at “reasonable” prices ahead of last year’s intervention.

Senex Energy, which is owned by South Korea’s Posco and is one of Australia’s biggest domestic gas producers, said the government’s actions also derailed more than $1 billion in planned investment in new supply from Queensland’s Surat Basin that customers were last year falling over themselves to access.