Candidates were asked whether they supported removing GST on fruit and vegetables.
Mr Davidson said GST was too high.
"The problem with taking it off fruit and vegetables is that you end up leaving it on things like frozen peas. Taking a few cents off the price of a cabbage won't make a lot of difference."
Mr McDonald said the Green Party's policy was to not remove the GST on fruit and vegetables.
"However, we do have a policy of raising the minimum wage immediately to $17 an hour, then to $20 an hour in three years' time. We will lift benefit levels. If we lift people's incomes, then we don't need to talk about subsidies to talk affording healthy foods."
Jonathan Hartfield, a retired doctor, asked the candidates if they believed New Zealand's defence force was still necessary.
"We have no enemies. Why do we spend $10 million per day on an army? " Dr Hartfield asked.
Ms Hipango noted that North Korea had just fired a missile towards Japan.
"We are very far removed, but we are still very close to these global threats. The reality is that we need to have security protective measures in place."
Mr Rurawhe said New Zealand had to play its role on the world stage.
"We want to be a responsible global citizen. We have to look after our own interests as well. But I do make the point that we will not enter into any conflict without the support of the United Nations."
Mr Tamati said New Zealand was a vulnerable country, and had few defences. He said having a defence force enabled New Zealand to build relationships with other, more powerful countries.
Former Whanganui District councillor Allan Anderson asked a question about whether farmers should be taxed for water use, and how this would affect particularly Canterbury farmers who are high irrigators.
Ms Patrick got the biggest cheer of the night with her response: "I think it's critical that we get serious about what's happening in Canterbury. That is not a suitable place for dairy farming. It doesn't get enough rainfall and it hasn't got the right soils. There is a public health warning in South Canterbury that says pregnant women should not use the water, and this is directly related to nitrate run-off in the aquifers."
Ms Lewis said members of Irrigation New Zealand had met with the Labour Party's environment spokesperson, David Parker, to talk about Labour's plans to tax farmers use of water.
"They have since advised that Labour's water royalty is not going to result in a significant increase in the cost of vegetables and milk. We need to clean up our waterways. Water is not an infinite resource - it is a finite resource."
Mr Skipworth said NZ First did not believe in taxing farmers for using water.
"However, we do believe in not allowing so much of our water to go overseas to all these bottling places."
The event was also streamed live on the Wanganui Chronicle's Facebook page, where it was watched by nearly 3000 people.