Prime Minister John Key says his name was used without his authority in correspondence between Bronwyn Pullar and her insurer.
On Thursday Mr Key was dragged into the widening ACC scandal and forced to deny a report he was part of a group of senior National Party figures who backed Ms Pullar's bid for a $14 million insurance payout.
Ms Pullar is the former National Party insider and ACC claimant at the centre of a privacy furore at the state-owned corporation which has raised questions of cronyism and exercise of political influence within the party.
TVNZ current affairs programme Close Up said it had received a letter written by Sovereign Insurance to former National Party president Michelle Boag in 2007.
The letter named 28 people, among them prominent National Party figures including Mr Key and former Prime Minister Dame Jenny Shipley, as supporters of Ms Pullar as she sought a $14m payout from the company in relation to injuries she suffered in a 2002 cycling accident.