ACC will challenge a decision to give a Christchurch volunteer compensation when, after the February 2011 quake, he was diagnosed with Post Traumatic Stress Disorder.
Builder Bill Toomey helped to pull people from the collapsed PGC building, where 18 people died.
Two years later he was diagnosed with Post Traumatic Stress Disorder (PTSD).
His claim was initially denied because his mental health injury wasn't triggered at work, but he took his case to court and won.
Toomey says news that ACC now plans to appeal that decision is like a punch to the gut.
He says it'll be at least a four-month wait for the decision on the appeal.
An ACC spokesman said it would "definitely" pay Toomey his full entitlements as "appeal proceedings have no impact on the outcome of a prior decision".
The corporation's decision to seek leave to appeal to the High Court was in order to seek clarification on a point of law - not to prevent Toomey getting compensation.