The public is highly polarised about whether the "tea cup tape'' should be released, a poll suggests.
Prime Minister John Key and Act Party candidate John Banks have both refused to give authorisation to release the tape, containing a conversation between the two which they thought was private.
A nationwide HorizonPoll found that 53 percent of people do not believe the politicians should authorise the public release of the recording, while 46.9 percent think they should.
The poll also shows that 54.9 percent of people believe the recording was a deliberate ploy by the media, while 15.9 percent believe it was inadvertent, 29.2 percent are not sure.
Asked if the Herald on Sunday, which has the recording but decided not to publish, or other news media should publish it now, 49.4% said no, 39.5% yes and 11% said they are not sure.
The poll suggests the affair has been damaging to the Prime Minister's reputation, with 41.9 percent saying it has made him less credible, 6.2 percent more credible and 47.4 percent saying it makes no difference.
Among National Party supporters, 17.7 percent think the issue has made the Prime Minister less credible and 12.3 percent more credible -- a net credibility loss of 5.4 percent.
Thirty-nine percent think it has made Mr Banks less credible, 3.2 percent more credible.
The poll also asked whether the issue has impacted New Zealanders' view on the credibility of the Herald on Sunday, with 43.1 percent thinking it made the newspaper less credible and 11.8 percent more credible.
It has also been damaging to the news media in general, with 38.6 percent believing has it made it is less credible, 9.8 percent more credible.
The poll questioned 2,874 adult New Zealanders and has a margin of error of +/- 1.8%.
