The Nationals’ net-zero commitment has been effectively reaffirmed after a push to scrap the policy, but the party’s debate has drawn internal and external criticism.

The Nationals leader staved off an internal push at the federal conference to scrap the policy of net-zero emissions by 2050, but party members agreed to a moratorium on large-scale renewable energy projects until environmental laws were amended.

David Littleproud said he was not against the move to renewables, but it needed to be balanced with coal and gas during the transition to avoid putting too much of the cost onto regional Australians.

Mr Littleproud said tearing up vegetation and prime agricultural land which would impact food security and prices was not the way to move ahead with the transition.

Conservative elements of the party were overruled when their motion to abolish the net-zero policy was amended to call on the parliamentary party room to “take a practical approach” to emissions reduction and ensure policies don’t negatively impact farmers.

Conservatives accused moderates from Liberal-aligned Queensland inner-city seats of stacking the vote against regional Nationals, who failed to pass the original motion.

This has been disputed by other party members who said inner-city voters included lifetime party members who had moved from the regions after retiring and pointed to the fact the motion was resoundingly defeated anyway.

Conservatives are also pushing for a federal party room vote on the issue amid confusion over whether a Barnaby Joyce-brokered deal with Scott Morrison to support net-zero in exchange for a multibillion-dollar fund is automatically woven into any new Coalition agreement.

Some argue the circumstances have changed due to Labor’s policy in government, but senior party members say election policy is automatically rolled over and operates until changes are announced.

Mr Joyce spoke against the net-zero policy at the weekend’s conference, seconding the abolition motion that originated in his electorate.

Senior Liberal and shadow cabinet member Simon Birmingham said it was not unusual for MPs to speak on policy motions at conferences, after questions were raised over whether Mr Joyce should remain in shadow cabinet.

Liberal MP Julian Leeser was forced to resign from his senior role earlier this year to campaign for the Indigenous Voice against official party policy.

“I note that the weekend contributions were at the National Party federal convention, with debate initiated by grassroots members around policy matters,” Senator Birmingham told AAP.

“It’s not unusual for members of any political party to engage in those grassroots policy debates.”

He said any consequences for Mr Joyce’s comments at the Nationals conference were for the leadership to decide and net zero by 2050 was a “strong and absolute” Coalition commitment that would be taken to the next election.

Cabinet minister Penny Wong slammed the Nationals for considering walking away from net zero and took aim at promotion of nuclear energy, saying it was on track to become five times more expensive than wind and solar energy in 2030.

Independent MP Helen Haines, from regional Victoria, said it was a scandal the Nationals were considering abandoning the policy as rural Australians were at the forefront of the effects of climate change.

-AAP