Barnaby Joyce has threatened to blow up government business after failing to overthrow Michael McCormack in a Nationals leadership coup.
The former Nationals leader has warned Scott Morrison the failure to put any of his supporters into the ministry after the spill has created a group of rebels.
Mr Joyce and his rump of disgruntled allies are now threatening to cross the floor and block coalition legislation as payback.
"You can't take my vote for granted ... I'll be looking at everything," Nationals MP Llew O'Brien told The Australian on Friday.
Prime Minister Scott Morrison was not fazed by the possibility.
"When a member makes a decision on how they would vote ... they do so on the basis of a long-held conviction and that is afforded to every coalition member of parliament," he told reporters in Townsville.
Cabinet minister Mathias Cormann also downplayed the threat.
"I don't believe that's what will happen," he told Sky News.
"Obviously in the coalition on matters of strong personal conviction on specific issue it's always open to individual members to take a particular position."
Senator Cormann said previous examples of Mr Joyce crossing the floor were a long time ago.
"That hasn't happened for a very, very long time."
But Darren Chester, who was returned to Cabinet after the spill, said Mr Joyce's past record could be more telling.
"Barnaby crossed the floor 28 times as a senator, it's hardly news that he's thinking about his options at some point in the future," he said.
"Barnaby's a strong campaigner for his community - I'm sure he'll act in the interests of his community."
Opposition Leader Anthony Albanese said Mr Joyce is "on the hunt", and his comments exposed division.
"That has real implications for the coalition government and its unity," he said.
Former resources minister Matt Canavan quit the cabinet to back Mr Joyce in the coup and has not been returned.
Key allies of Mr McCormack were promoted, including Mark Coulton and Andrew Gee.
Mr Joyce also spoke out against a bid to change Nationals rules to prevent leaders being knifed by requiring two-thirds partyroom support to allow a leadership spill.
"I am fervently opposed to the mooted change to diminish access to senators and members determining their leader," he wrote in an opinion piece for The Australian.
"I am against it because its purpose is to curtail access to a vote, which is obviously a removal of a democratic attribute of our party."
Australian Associated Press