National would have to "have a sit down" and work out how to diversify its caucus, Maharey said.
"One of the key things that National's going to have to do ... is they're going to have to start looking like New Zealand."
National should look for a candidate to "capture the mood of the times," Maharey said, but he thought it would be "sensible" to stick with Collins "while they worked things out".
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Maharey predicted National would move to somebody else after Collins, before settling on the final candidate.
Currently, the line up of Collins and Gerry Brownlee, "looked like the past," despite their "long, successful careers," Maharey said.
"These are good people, but they really just belong to a view of the world which doesn't really exist amongst most people."
National should take heed of what was happening in the US, to avoid becoming a "rump party of white men".
"I think this is the same lesson for a country like [ours]. Highly diverse, very different, young population - you've got to have people who really represent that - and the National Party just simply does not look like that."
Also in today's interview: Maharey looked at how the newly elected Government would affect farmers.