He said while people do vote on policies, leadership is also important.
"He's the skipper of Labour just like I'm the skipper of National. You would expect whoever the leader is to be the person supporting their candidates. I'm on the hoardings of every candidate. What I'm saying to the people in that community is that I stand by that candidate and am backing that person."
The comments drew a retort from Mr Goff, who said Mr Key was clearly worried that "New Zealanders will vote on issues that matter rather than photo ops".
"John Key calls himself the 'skipper' of his party. Well, he can certainly claim credit for running this country aground."
He was happy to go toe-to-toe with Mr Key at any time, and accused Mr Key of being "gutless" and failing to front up for tough media interviews.
"We'd rather stand by [our policies] this election than rely on simply smiling and waving."
Labour's campaign spokesman Grant Robertson said the party was taking a different approach to emphasise the stark policy differences between the two parties, rather than viewing it as a "popularity contest".
Mr Goff would still appear on the party's television advertisements - which began screening last night and focus on opposing state asset sales - and in televised leaders' debates.
Asked if it was an admission that Mr Goff could not successfully go head to head with Mr Key, Mr Robertson conceded that Mr Key was "an extremely popular Prime Minister" but Labour had chosen instead to promote its policies and team.
Claire Robinson, a political marketing commentator at Massey University, said it was an obvious attempt to push Mr Goff into the background given his poor personal polling.
She could not understand the decision not to hold a campaign launch, saying it was a missed opportunity, as was not putting Mr Goff on billboards to try to sell him to voters.
"Labour's trying to say they're not doing it on personality, and focusing on the policy - but it is actually about personality. They can't avoid it. It's about policy and it's about leadership. And by not focusing on leadership, it's the elephant in the room and I don't think it's good strategy to avoid it," she said.
National will hold its campaign launch on Sunday in Auckland, as will New Zealand First.
The Maori Party will hold its launch in Wellington on Saturday and the Green Party will have theirs next weekend in Wellington.
