But what started out as a media event over a cup of tea in a Newmarket cafe has come to dominate national headlines this week over what was said in the "teapot tape" - a recording of the conversation between Mr Key and Mr Banks.
There has been speculation they talked about Don Brash's leadership of Act, and Winston Peters has claimed Mr Key made offensive comments about New Zealand First's elderly supporters.
Even before the cup of tea, Epsom voters were wary about tactical voting.
A Key Research poll of 500 of the seat's voters, commissioned by the Herald on Sunday and published on October 9, found 32.9 per cent support for National's Paul Goldsmith and 18.9 per cent for Mr Banks.
A Herald street poll of 47 Epsom voters 10 days ago found mixed support for Mr Banks, who has always polarised voters.
Some, like Parnell businessman Keith McConnell, admired Mr Banks' "no bullshit" style, while two Remuera businessmen summed up the tactical situation by saying they were waiting for a signal from Mr Key to determine their electorate votes.
Others, like Michael Wall, a 62-year-old Parnell resident and staunch National supporter, said the election was "the greatest opportunity to get rid of the selfish, self-centred Act Party".
Mr Banks maintains he can get there on his own, but placed a glossy brochure featuring a friendly picture with the Prime Minister and himself having the cup of tea on every seat at the Act campaign launch.
Mr Goldsmith is doing his best to be the non-candidate, campaigning for the party vote while politely thanking supporters who want him as their constituency MP.
On the left, where the Labour and Green candidates pulled nearly 8000 votes in 2008, Labour candidate David Parker is urging people not to split their candidate and party votes, while the Greens' David Hay is focused on raising the party vote by 50 per cent. With the Greens at 12.6 per cent in the latest Herald-DigiPoll survey, Mr Hay - at 16th on the party list - is on the cusp of making it into Parliament.
Mr Parker, Labour's associate finance spokesman, said he was standing in the blue ribbon seat to hold Act to account over its record and as a platform to explain Labour's economic policy.
In Mt Eden on the liberal western fringes of Epsom, Peter Lange, brother of the late Labour Prime Minister David Lange, is encouraging voters to "hold your nose" and vote for Mr Goldsmith. Mr Lange said his unofficial campaign was a counter-attack to Mr Key's "match fixing" and an attempt to "put Act out of its own misery".
* Find out more about your electorate and candidates with the interactive map at nzherald.co.nz/election-2011