The Deputy Prime Minister also said "geopolitical circumstances" - not climate change - was Australia's biggest threat and linked the profit of coal exports to the nation's ability to defend itself from invasion in an address to the Queensland Rural Press Club.

While not outright rejecting the carbon neutral policy, Mr Joyce voiced his strong disapproval, pointing to the rising price of energy in Europe as it purses net zero and the "mountain pressure" UK Prime Minister Boris Johnson was facing over his government's 2050 plan.

"We have walked into this path by reason of naivety, now reality is beating us with a stick," Mr Joyce said.

"We're [taking climate action] but we can't force China, Russia or Iran to comply with international climate policy.

"I don't mock the idealism. As you walk up the political hill you are the idealist as we walk down the other side you are the realists. I'm most definitely on the way down the political hill... so the realism is what I must offer you."

READ MORE:

Government convention that all ministers must publicly support government policy or otherwise resign from the front bench. Mr Joyce and the Nationals agreed to support the plan at the end of last year after weeks of negotiating with the Liberals.

It's believed a number of policy and funding concessions were made in exchange for the party's support, however the details have not been made public.

Mr Joyce warned Australia's last two oil refineries would be targeted by a "safeguard mechanism" tax, designed to reduce emissions under the 2050 carbon neutral plan.

"We've got two refineries left in Australia, that's pretty vulnerable... if you're trying to keep refining capacity here, I'll give you a tip: don't tax it," he said.

Mr Joyce said people only had to look at "demands China has already made on Australia" to see what the nation's greatest danger would be in the coming years.

"The biggest threat before your children is a change to geopolitical circumstances," Mr Joyce said.

"Those carrying coffins out of Ukraine churches are not focused on climate change, as the aggressor has never made it an item of negotiation for a ceasefire."

Australia had to become "as strong as possible, as quickly as possible", Mr Joyce said, or the nation would be "caught in the most brutal lesson of our time" in the imminent future.

"We can only defend ourselves if we can pay for that," Mr Joyce said.

"It needs money and money in Australia is made from exports. Our nation's second biggest export is coal. The price of thermal coal has hit $374 a ton, not bad for a product that apparently nobody is using.

"If you want to protect your capacity to determine who comes into your country, the investment that comes in, what you can say, where you can go, then you must be strong.

"We look at what's happening in the Ukraine and the one thing that comes across so loud and clear is nobody's going to help them. The people of Democratic Taiwan are also watching this."