"If they want to be in this Government, they'll be on the same page."
But he said MPs were entitled to their opinions.
"People are entitled to voice their opinion on things, they might think downstream some time in the history of this country this might be something that's happening, but as for something that's happening now? No," he told Stuff.
He made his comments after Mahuta yesterday said it was a matter of time before Te Reo Māori was compulsory in schools.
Jackson said in December last year that universally available and compulsory were one and the same.
Today, Ardern had no problem with Peters' comments.
"I've actually looked at his quote. He also says that those ministers are free to talk about the future and that's exactly what they were doing."
Peters today appeared to water down his comments.
"I said people can be enthusiastic, and they can push policies and probably can campaign on them in 2020. But it's not a policy that we are campaigning on or implementing now, as the Prime Minister has said."
Mahuta today denied she had been told off.
"It is fruitless looking for any type of division on this matter because we know the very real challenge for Reo revitalisation is to ensure we have the numbers of teachers in our schools who can deliver the curriculum in Te Reo Māori."
Jackson said Peters had always been very respectful of their views and they of his.
"I've always had great debates with Winston Peters over Te Reo.
"I haven't picked any divisions up within our party … but we know the views of the other parties and that's fine."