Nationals leader Michael McCormack has cast aspersions on the farming sector's aims to cut emissions over the next decade.
The National Farmers Federation has had a policy for almost two years for the sector to be "trending towards carbon neutrality by 2030".
Its 2030 road map also says Australia could become a global leader in low emissions agriculture, although cautions a poor policy response "could saddle farm businesses with additional costs".
The move towards carbon neutrality has been seized by Labor to back its commitment to bring Australia down to net zero emissions by 2050.
But the deputy prime minister is sceptical about the NFF aims.
"Trending towards and actually achieving might be two different things," Mr McCormack told Sky News on Wednesday.
"What the Nationals support is jobs in regional Australia and jobs in agriculture."
Asked whether he backed the NFF's plans, he said only that it was aspirational.
"It's aspirational by the NFF, good on them, and I support Fiona Simson and what the NFF stand for," he said.
"But the fact remains we want to make sure we grow agriculture."
Meanwhile, the latest quarterly carbon market report shows carbon abatement schemes reached a record 50 million tonnes in 2019 and is expected to increase again to 59 million tonnes in 2020.
Australia's total emissions in the year to June 2019 were 532 million tonnes.
The Clean Energy Regulator's report also estimates a quarter of Australia's electricity came from renewables by the end of 2019.
Australian Associated Press