Maori Party co-leader Tariana Turia says it is not appropriate for New Zealand On Air to stop programmes from being broadcast during an election campaign.
The broadcast funding agency is considering the move and has received legal advice after a programme about child poverty which it funded was broadcast days before the election on 26 November last year.
NZ On Air says it has been accused of political bias following the airing of Inside Child Poverty: A Special Report on TV3 on 22 November.
NZ On Air chairperson Neil Walter has said the agency only found out a couple of days before the programme was screened that it would be broadcast so close to polling day.
Mr Walter said the agency has to protect its reputation for political impartiality. "Personally, I don't believe the New Zealand public would expect or want to see their funding put into a politically charged scenario like that."
Tariana Turia is deputy chair of a new ministerial committee on poverty, established as part of the Maori Party's post-election deal with the National Party.
Mrs Turia told Radio New Zealand's Checkpoint programme on Wednesday that poverty is not a particularly politically-charged issue.
"We should never afraid to talk about what is the reality for some of our families and the situations they are in.
"Poverty has been an issue that all governments - and I mean all political parties that have been in government - have shied away from."
Mrs Turia says she supports freedom of speech.
Labour Party broadcasting spokesperson Clare Curran has questioned whether the National Party is interfering in NZ on Air.
Ms Curran says Prime Minister John Key's electorate chairman is on the agency's board and was the one who first raised concerns about the poverty documentary.
"Surely it's a good thing that during an election campaign for there to be robust political discussion about issues."
Broadcasting Minister Craig Foss has declined to comment, saying it would be inappropriate to get involved.
NZOA urged to steer clear
The Screen Directors Guild says broadcasters could be deterred from screening documentaries that are political if NZ On Air interferes with what can be aired during election periods.
The guild's acting executive director, Janette Howe, says the screening of the child poverty documentary was excellent timing because it received maximum viewership and sparked a healthy debate on the issue.
Ms Howe says it is the role of the Broadcasting Standards Authority to look at when a particular programme is aired and whether it is politically biased.
Electoral law specialist Graeme Edgeler believes NZ On Air should steer clear of this issue if it wants to be politically impartial.
Mr Edgeler says the agency risks losing its political impartiality by getting involved and should remain at arms-length when it comes to programme scheduling during an election campaign.
He says NZ On Air would be better off making sure the programmes it funds are balanced.
The programme's maker says the documentary was relevant and important and did not support any party.
Bryan Bruce says moves to restrict when programmes are played are an affront on democracy and a dangerous step towards a very controlled environment.