"If emissions are to be reduced then nuclear is the perfect option," said Mr Johnsen a day after Mr Barilaro blindsided Premier Gladys Berejiklian during a television interview on Tuesday by supporting One Nation MP Mark Latham's private member's bill to break the nuclear ban.

Mr Johnsen said "Yes yes and yes" to questions about whether he backed Mr Barilaro's comments, and whether the Upper Hunter was well placed to support nuclear energy and a small modular nuclear reactor.

"The Upper Hunter is a good fit because of its extensive energy infrastructure and opportunity for growth. It's important to have a rational, sensible discussion on nuclear energy in the context of modern technology," he said.

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NSW Labor leader Jodi McKay said Mr Barilaro "threw the Premier under a bus" when he committed his party to vote for the One Nation bill while Gladys Berejiklian was unable to say what the position of her Government is.

Ms McKay said she had trouble taking Mr Barilaro seriously on nuclear energy.

"Mr Barilaro and the nuclear industry have one thing in common: many of their promises never happen," she said.

Port Stephens MP Kate Washington and Newcastle MP Tim Crakanthorp slammed the Nationals' move, after Mr Crakanthorp in August condemned the Nationals' "reckless support" for nuclear power in NSW at its 2019 conference.

"Nuclear power is the most expensive form of new build energy generation which would condemn homes and businesses to even higher electricity costs," said Mr Crakanthorp.

"Nuclear power involves the production of toxic waste, hazard to the environment and human health for tens and thousands of years."

During the parliamentary debate in August Mr Crakanthorp called on Ms Berejiklian to "rule out nuclear power in NSW, including my electorate of Newcastle".

Ms Washington described the push for nuclear power as an "unhelpful distraction from the urgent need to invest in clean energy and renewables".

"Not only is nuclear energy the most expensive, no-one wants a nuclear reactor in their back yard. Will any member of the government be willing to put their hand up to have a nuclear reactor in their electorate?" Ms Washington said.

During his interview on Tuesday Mr Barilaro said nuclear power was "the piece that's missing in the conversation" that extended to exporting uranium, "bringing back waste" and running waste facilities.

It also included establishing "small modular reactors which in my mind are the iphone of reactors because they are smaller, smarter, cheaper", with the ability to provide baseload power and zero emissions, Mr Barilaro said.

Small nuclear reactors were not like "Fukushima, Chernobyl, Three Mile Island" or "the reactor that Homer Simpson runs on The Simpsons", he said.

The recommendation was backed by three Liberal MPs and one National Party MP.

Mr Barilaro's comments were made on the eve of the release of an Upper House inquiry, chaired by Liberal Taylor Martin, that recommended removing the state's long-standing legislative ban on uranium mining and nuclear power and backed Mr Latham's bill.

The inquiry defined small modular reactors as generating 300 megawatts or less, 20 metres high and five metres in diameter, which "borrow heavily from previous technology".

The inquiry heard evidence from an American company that has spent more than $1 billion developing a small modular reactor that will have its first use at an Idaho power plant in 2026.

The inquiry acknowledged that "the merits and benefits of small modular reactors were not universally accepted by all inquiry participants", with dissenting views from environment groups and unions.

Opinions on the safety of nuclear power were also "far from unanimous".

"The Minerals Council of Australia sought to impress upon the committee that accidents in the nuclear power industry are extremely uncommon, a contention borne out by accident statistics since the advent of nuclear power in the 1950s," the inquiry noted.