Hipkins has ruled out both "under a government I lead", despite the measures being openly supported by some of the party's MPs.
Bishop claimed that at an event last night the MP for Taieri said while she backed the "captain's call", she would like to "leave a transparent and fairer tax system" as a legacy - including a capital gains tax.
Both Labour's potential coalition partners - the Greens and Te Pati Māori - back putting more of the tax burden on the wealthy than at present.
"Labour loves tax like a shark loves blood, and Hipkins' colleagues are circling," Bishop said.
Leary rejected Bishop's claim.
"The Labour tax policy is clear - we are not proposing a wealth tax or capital gains tax if re-elected," she told RNZ in a statement.
"Caucus has agreed that position. What I conveyed was that it could be something for the future, but it is not a policy for our next term."
And on National's claim the Labour caucus would roll Hipkins to introduce new taxes: "What a load of rubbish. The person recording the meeting conveniently forgot to mention that I also said I think we have a fantastic prime minister who I see leading us into the future.
Leary refused to be interviewed, saying: "Sorry, because the story is such a beat-up I don't intend to participate further."
