"And I don't know why," Mr Joyce, the MP for New England, said.

Mr Joyce, along with fellow Nationals - Senator Matt Canavan and Lyne MP David Gillespie - took to the stage for a question and answer session at a Hunter Business Chamber lunch at Newcastle City Hall.

They are in the Hunter for a two-day visit after visits from Deputy Prime Minister Michael McCormack and Resources Minister Keith Pitt, along with Nationals NSW Senator Perin Davey.

The Nationals believe Joel Fitzgibbon's federal seat of Hunter is "in play" and appear likely to put more than the usual amount of effort into the electorate after the 2019 election ate considerably into the ALP veteran's margin, with the Nationals and One Nation's Stuart Bonds effectively splitting the conservative vote.

At a media conference after their business lunch session, Senator Canavan, Mr Joyce and Dr Gillespie summarised much of what they told their business audience - that they believed the NSW state government's electricity "Roadmap" was a blunder - a message they said they would continue to push even if it put them at odds with the Coalition state government.

Asked how Australia could meet its obligation under international climate treaties without doing away with coal, Senator Canavan said we were "already meeting our obligations and there is no need to shut down the coal industry to meet that target".

"And I don't think we should be going any further than we need to, certainly not before other countries start picking up their act," Senator Canavan said.

As an example, he said New Zealand Prime Minister Jacinda Adern was a favourite of the progressives, but she had "exempted their coal industry - and yes, it's smaller than ours - from their net zero emissions targets."

"Until other countries have, why should we [do things that] cost jobs in Australia?" Senator Canavan said.

David Gillespie, a gastroenterologist and consultant physician at Port Macquarie hospital before entering federal parliament in 2013, said that based on what "energy experts" had told him, the NSW government's Electricity Infrastructure Roadmap was "a bad plan" that will add substantially to power costs.

He said the "last bit" of the accompanying legislation was an "electricity infrastructure fund" to be "established and maintained" by payments from companies involved in electricity transmission - defined as "distribution network service providers" in the legislation.

"They will be charged a fee that will passed on to you, so I think it's bad economics and bad engineering to base the grid on intermittent sources," Dr Gillespie said.

"You will have blackouts and brownouts and it will be super expensive, because the more renewables that are integrated, the less efficient the grid will be, and that's why costs have gone up."

Mr Joyce said one of the "noxious things" about the NSW government Roadmap was "them saying we're going to meet our policy desires with Hunter Valley jobs, that's the trade-off.

Senator Joyce said the push for renewables was having a "very minor effect" in white collar electorates such as "Annandale and St Kilda and Toorak, where power costs were not "a critical" factor.

"But where it is having a major effect is on blue collar jobs and the mining industry," Mr Joyce said.

Running through the range of energy sources, Mr Joyce said "coal was like "Yahweh [God] in the Old Testament, you get stoned to death if you mention it, odd as that is".

"Gas depends on fracking," Mr Joyce said.

"Nuclear, you can cart it through town and give it someone else but you can't use it yourself, I don't know why.

"Wind power? I'll take you towns that will tear you to pieces over wind turbines if you suggest them.

"Pumped hydro requires dams and people don't believe in dams and there's a bitch fight about that now, even in the Snowy Mountains.

"Solar? I'll take you next to a solar farm, and watch the fights that happen there.

"So, I tell you what, I've got a really smart idea. Build high-efficiency, low-emissions, the best technology, coal-fired power in the world, develop it in Australia and export the technology, with the product, and show how you can do it, in the Hunter Valley."

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