Labour is accusing National of political interference in the public broadcasting agency New Zealand on Air.
The independent Government funding agency is looking into whether it can require broadcasters not to screen programmes likely to be election issues during the election campaign period.
It comes after board members questioned TV3's decision to screen a documentary about child poverty four days before last year's General Election.
NZ on Air provided $105,400 for the documentary, called Inside Child Poverty.
Labour's broadcasting spokeswoman Clare Curran says NZ on Air should be politically neutral, and she is concerned the body has been spooked into seeking the legal action.
"What concerns me is that they want to shut down public discussion, and there appears to be moves to use an agency to do that," she told ONE News.
Emails released under the Official Information Act to the Scoop website show concerns about the documentary were raised by NZ on Air board member Stephen McElrea, who is also Prime Minister John Key's Helensville electorate chairman.
Curran says Key needs to answer questions about whether he spoke to McElrea about the complaint before it was laid.
"Was he kept in the loop about the decision to pursue legal advice to shut down political debate about controversial issues before an election? And was Stephen McElrea acting as a NZ on Air board member or as an official of the National Party?" she said.
Curran says NZ on Air should be encouraging programmes with political implications, and as long as those programmes are balanced and both sides have their say, they should be aired.
Neither McElrea nor anyone else from NZ on Air or the Government would talk to ONE News today.
NZ on Air complained to TV3 about the scheduling but says it did not try to change it.
NZ on Air board chairman Neil Walter told Radio New Zealand the agency feels it needs legal advice for any future issues.
"Personally I don't believe the New Zealand public would expect or want to see their funding put into a politically charged scenario," he said.
"If you get burned once like that, you look around to see what can be done to avoid the situation coming up again."
Curran said she is concerned about what that might mean for news and current affairs programmes.
"Would we see Q+A being taken off air during and election campaign? Would Radio New Zealand be restricted in what it can and can't do? That's just wrong."
