Labour accuses Finance Minister Bill English of breaching the Cabinet Manual by appearing in a promotional announcement for an upcoming series by TVNZ 7 on the economy.
Labour's finance spokesperson David Cunliffe also wants Mr English to spell out what changes he made to the script for the advertisement.
Mr Cunliffe says Mr English has breached Cabinet rules by appearing in a promotional announcement which looks and sounds like a political broadcast.
He says there is a clear perception of a conflict of interest as Mr English is one of Televison New Zealand's shareholding ministers.
Mr Cunliffe says Labour is making a formal complaint to TVNZ about the promotional announcement on Wednesday.
Both Mr English and TVNZ have defended the ad, with the minister saying he believes it looks quite good.