The smirks quickly disappeared when Mr Key rubbished what a Labour and Greens-led Government would look like.
Responding to comments made about housing, Mrs Turei said both Mr Key and Mr Cunliffe ignored that people outside Auckland and Christchurch also had housing issues.
"The whole country has a housing crisis," Mrs Turei said, referencing damp, uninsulated rental properties in Dunedin.
Dr Norman added that he agreed with Mr Cunliffe that there needed to be tighter restrictions on foreign ownership of New Zealand land and houses.
"We think it's important to take heat out of the housing market . . . foreign buyers are a big part of that."
There was no way some Kiwi families trying to get into farming could compete with foreign buyers, Dr Norman said.
"It's like the Lochinver situation, there still are New Zealand buyers, they're just not going to pay as much."
Auckland also needed greater-density housing, he said. "We can't just keep sprawling."
Following the debate, Dr Norman said he was disappointed that climate change wasn't brought up in the debate. "I think it's critical."
Mrs Turei also criticised the lack of debate on inequality, highlighting the Green party's policies to tackle the issue.