Loading In an email to members on Wednesday, the Nationals' NSW state director, Ross Cadell, and chairman Bede Burke accused Senator Molan and his backers of breaching the Coalition agreement and significantly harming the National candidate's chances of winning a seat. This left the junior Coalition partner with "no choice but to follow suit", the pair wrote. "Supporters of Liberal senator Jim Molan have taken it upon themselves to campaign for a 'below-the-line' vote, which in our view breaks the Coalition agreement and seriously harms the chances of a Nationals senator being elected," they said. "We are not taking this extraordinary step lightly ... this is not something we want to do, but we need every one of our members to vote below the line for Perin Davey and Sam Farraway, and to encourage everyone they know to do the same."

Loading Mr Cadell said the Nationals were primarily responding to Senator Molan's "mean" decision to take out advertisements in regional newspapers, directly targeting their voter base. "We're disappointed," he said. "We have had a tight Coalition for a long time that has worked very strongly. Jim's an honourable guy, he's done a lot of things in his life well. But at a time when a bit of loyalty and a bit of team spirit [is needed], it's just disappointing." Senator Molan's renegade campaign is also causing grief in his own party, with Tony Abbott's campaign team angry that Molan supporters are trying to poach volunteers from Mr Abbott's hard-fought campaign to retain Warringah, and Liberal MP John Alexander caught on tape advising someone how to vote for Senator Molan - in defiance of party instructions.

Defending himself on Wednesday, Senator Molan blamed former prime minister Malcolm Turnbull for making below-the-line voting easier in his 2016 suite of Senate voting reforms. Voters now need to number only 12 boxes below the line rather than every box. "Malcolm Turnbull gave us this option, that's the key thing," Senator Molan told 2GB radio. "That made it feasible. I'm not asking people, my colleagues out there, to kill themselves over this. But the people now have the ability to speak independently of factions." Mr Joyce - who has argued for the Nationals to run their own Senate ticket in NSW - said the Liberal Party had "fired the first shot" in the war and said the furore had the ability to cause "utter chaos" if it drove the long-running Coalition partnership apart. Nationals leader Michael McCormack has come under criticism for failing to secure the party a better deal. Credit:Dominic Lorrimer "This is not a marriage, it never was a marriage, it was a business arrangement," he told The Sydney Morning Herald and The Age. "If you do over your business partner, the partnership won't go so well. If the Liberal Party and the National Party were separate parties in every seat, that would be utter chaos."