A Liberal backbencher has accused the NSW Deputy Premier and Nationals Leader John Barilaro of “bullying” the Premier over the koala protection policy.Key points:There has been building tension this week over an update to a koala protection planning policyThe Nationals want an emergency cabinet meeting but NSW Premier Gladys Berejiklian is refusing to bow to pressure.The Nationals are concerned the updated policy will limit building on farmsCatherine Cusack has spoken out against Mr Barilaro, in an escalating conflict between the Coalition partners.Four Nationals MPs are threatening to plunge the NSW Government into minority if the koala protection policy isn’t changed — and they have the support of their leader.They’re concerned it will limit land use on farms and the ability to rezone areas for development.Under the new policy, more trees are classed as koala habitat which will restrict the clearing of land.It follows a declaration by Mr Barilaro to the media today that the four MPs will move to the crossbench. Liberal upper house MP Catherine Cusack criticised John Barilaro’s announcement.(ABC News)Ms Cusack accused Mr Barilaro of treating NSW Premier Gladys Berejiklian with “extreme contempt”.She said the four Nationals MPs had been “herded into a corner”.”The whole strategy is 100 per cent bullying.”She said the koala State Environmental Planning Policy (SEPP) had been updated “at the behest of stakeholders that came from their own electorates” after an “exhaustive” process. The bill increases farmers’ responsibilities to look for koalas before clearing land.(Dave Hunt: AAP)”I think it’s fair to say Liberal members … are really stunned and bewildered by this extraordinary behaviour by the leader of the National Party, who’s also the Deputy Premier who we support in Parliament to deliver stability and loyalty to the Premier, the Cabinet and the Government,” she said. Mr Barilaro said the four MPs had his full support. “This is the right thing to fight for on behalf of the community,” he said. “It’s not about destruction of koala habitat. The protection SEP does not do anything to save a koala, but puts a nail in the coffin for farmers. “That is not what we were elected to do. We’ll find a solution.”Ms Berejiklian is refusing to bow to pressure from National MPs who want an emergency cabinet meeting to resolve the tension over the koala protection plan. On Monday, Mr Barilaro wrote to the Premier asking her to hold an unscheduled meeting next week ahead of parliamentary sittings.