A leaked letter reportedly reveals that Prime Minister John Key lent his support to a multimillion-dollar private insurance claim by the woman at the centre of the ACC privacy breach.
Mr Key denies that, saying he was never part of a support and advisory team to help National Party insider Bronwyn Pullar in her attempt to claim up to $14 million.
The letter from private insurer Sovereign, leaked to TVNZ's Close Up programme, claims Mr Key was among 28 high-profile people who backed Ms Pullar in her claim.
Ms Pullar's fight for compensation over a 2002 cycling injury has already caused headaches for the National Party, drawing in former president Michelle Boag and leading to the resignation of senior minister Nick Smith.
Ms Boag acted as a support person at a meeting with senior ACC managers in which Ms Pullar allegedly threatened to go public with information she accidentally received about 6700 ACC claims.
At the time, she had already received an income protection payment from Sovereign, understood to be more than $1 million.
The letter from Sovereign, sent to Ms Boag before Ms Pullar's claim was settled in 2007, names 28 people as part of a claims support and advisory team for Ms Pullar.
Among them are Mr Key, former National Prime Minister Jenny Shipley, Sir Selwyn Cushing and National Party minister Wayne Mapp.
In a statement to TVNZ, Mr Key said he had not been involved in any claims support or advisory team for Ms Pullar.
"The claim in the letter that I was part of such a team in 2007, or indeed any other time, is wrong."
In the letter, Sovereign said Ms Pullar's claim of up to $14m was "greatly in excess" of her entitlement.