Labour leader David Cunliffe did little to support his caucus colleague's suggestion.
"I don't think this one's going to fly. There's a lot of scientific work to go under the bridge before moas are going to be flopping around in Wainuiomata.
"The moa's not a goer."
Prime Minister John Key joked that there were a few moas in the Labour caucus already, while senior minister Steven Joyce facetiously called it "inspired thinking".
"Why stop there? Why not bring back some old Labour Party prime ministers ... some extra talent for their caucus. This is a huge vista of opportunity," Mr Joyce said.
But Mr Mallard insisted de-extinction was inevitable.
"I'm absolutely certain that at some point in the future, a whole pile of species that area currently extinct will be brought back to life ... The moa will be a goer, but we're talking to 50 to 100 years out."
He stressed that he did not want 240kg, 3.5m-tall moa roaming the hills behind Wainuiomata.
"They would be dangerous. But the ones 1.3m-tall (and 1.8m-tall) don't weight much more than turkeys. I'd like ones I could pat on the head, rather than the ones that are going to bowl us over."
He said there were parallels with Jurassic Park, "which of course most of us thought of as absolutely impossible and ridiculous".
"I'm absolutely serious that we should be taking advantage of science as it develops. A lot of people poopoo-ed early scientists, but this work is something which is logical, it is already happening around the world, and in New Zealand ... we should at least start talking about it."
He said it was not official Labour Party policy, nor a diversion from more important political issues.
"I don't think this is a distraction at all. It's a minor, long-term idea."