Mr Nash said regional airfares were "horrendous".
"As somebody who's been travelling to and from Auckland for two and a half years, we get absolutely rorted. I actually think it's a barrier to business in Hastings and Napier. What I see in their [Air NZ's] pricing is monopolistic behaviour," he said.
Tukituki National MP and Commerce Minister Craig Foss said he agreed with John Key's suggestion Air NZ should reduce regional airfares.
"I agree with the Prime Minister that Air NZ needs to continue the work it's doing while making sure it reduces prices to the regions, if it can ... Air NZ has a crucial role in the development of Hawke's Bay, and I would expect them to work positively with our region." Tukituki Labour candidate Anna Lorck said Air NZ's regional airfares were "another example of the Government neglecting our region".
"Air NZ is making profits out of the regions and in doing do stifling regional economic development. The costs are far too high and this must be addressed," Ms Lorck said.
Napier National candidate Wayne Walford agreed "everyone would like to see a reduction" in regional airfares.
Napier Green Party candidate Paul Bailey said he would welcome competition on regional routes, but "in the long term we have to wean ourselves off our love of air travel and use more carbon efficient methods of transportation".
Ikaroa-Rawhiti Labour candidate Meka Whaitiri said regional airfares were "overly priced," particularly to Napier and Gisborne.
"I would support any initiative to bring them into a more reasonable range as a way to encourage more tourism to these areas, creating much needed jobs," Ms Whaitiri said.
Ikaroa-Rawhiti Maori Party candidate Marama Fox said the airfares were inhibiting Ikaroa-Rawhiti residents from accessing major cities for tertiary education and work.
"Further, the tourist market is likewise impacted by the daunting cost of convenient travel to our region," Ms Fox said.
Napier Conservative Party candidate Garth McVicar said the high cost of flying to and from Napier had always frustrated him.
"Competition is the only way to pull the process down. Our regional leaders need to team up and make a submission to Jetstar to entice them to the Bay."
Air NZ rejected claims it was price-gouging passengers on regional routes, and said there was ample domestic competition.
Hawke's Bay Airport chief executive Nick Story said the airport had had discussions with Air NZ regarding its regional airfares.
"Air NZ has a monopoly on regional flights," Mr Story said.
However, the carrier had recently increased seating capacity in and out of Hawke's Bay, which he hoped would have a positive impact on pricing.
Asked if he thought Air NZ's regional airfares should be regulated, he said: "We would prefer that a focus on customers and a desire for a long term and mutually beneficial partnership with the regions, as opposed to regulation, will determine their pricing of regional services."