Chris Hipkins is urging the Prime Minister to set some "clear boundaries" for Winston Peters after his comments against the media.
Peters' remarks weren't acceptable and "potentially in breach of legislation", the Labour leader said.
In the past couple of days, Peters has questioned the independence of the media and said the $55 million Public Interest Journalism Fund (PIJF) from New Zealand on Air was a "bribe" to journalists.
On Monday, Peters took it upon himself to issue direction to state-owned broadcasters in response to a question about his policy about public agencies narrowing the use of te reo Māori.
"Well we will see the speed in which TVNZ and RNZ, which are taxpayer-owned, understand this new message," the Deputy Prime Minister said.
When it was put to Peters the state broadcasters were independent, he said he had "never seen evidence" of that in the past three years.
The Radio New Zealand Act 1995 states no responsible minister or any other minister may give a direction to the public radio company in respect of the gathering or presentation of news or the preparation or presentation of current affairs programmes. TVNZ's Act has the same clause.
Hipkins, speaking to AM, said Prime Minister Christopher Luxon needed to send Peters a clear message.
Hipkins wanted Peters, as the Deputy Prime Minister, to realise his responsibilities.
Among those responsibilities were to "adhere to the law and also adhere to Cabinet collective responsibility", Hipkins said.
He said Peters didn't appear to be doing that.
However, Hipkins admitted he agreed with his former Broadcasting Minister Willie Jackson the PIJF may have gone too far in requiring media companies to sign up to a Treaty of Waitangi clause.
The PIJF's guidelines stated recipients must "actively promote the principles of partnership, participation and active protection under Te Tiriti o Waitangi".
"That's not necessarily the criteria I would've used, I agree with Willie on that but I also think it's important that New Zealand on Air make those decisions independently," Hipkins said.
He reiterated Jackson's comments about the former Government having no say in which companies got funding from the PIJF.
"That was decided by New Zealand on Air and they set the criteria and they set the criteria for that."
New Zealand on Air funded some "incredibly important" content in Aotearoa, Hipkins said.
"In terms of the Public Interest Journalism funding, it went to things like local Government so that the local papers that you've got actually were covering decisions that were being taken by your local council and so-on - and I think that was actually good for democracy.
"I certainly didn't see any suggestion that coverage was politically unbalanced."
Jackson earlier told AM he never told any journalists what to say and said there were laws in place to ensure no influence was had on newsgathering or reporting.
"We were re-shaping the whole media landscape at the time, so I was really proud of the $55 million that was allocated."
The media "hardly gave us an easy ride" despite the PIJF, he said.
