Giving branch members a say would prevent embarrassing results such as Penny Wong being placed at second on the South Australian ticket behind right-wing numbers man Don Farrell, as happened before the last federal election. Western Australian senator Louise Pratt lost her seat last year after a deal between the Right-aligned Shop, Distributive and Allied Workers Union and the Left-aligned United Voice union installed Jo Bullock at the top of the ticket. United Voice's WA branch was the only Left-aligned union to oppose the in-principle agreement to back the 50:50 system struck at a meeting of the Left at Trades Hall in Sydney last Saturday. But sources said the Victorian Left, led by Senator Kim Carr, could push back and splinter the united front before conference in favour of the status quo. Sources on the Right said the plan would increase the influence of unions because of the power of the 50 per cent bloc vote. "In this scenario, if I get six or seven union secretaries on board on something, I get my way," said a senior party figure. With numbers between the Right and the Left at the upcoming conference almost evenly balanced, the reform has a good chance to succeed if the Left remains united, but Mr Shorten's position will be critical.

During a key speech in April last year, he promised that the party under him would be "setting a new standard for selecting Labor senators". "I have instructed our national secretary to work with the national executive and the Western Australian Labor Party to recommend the best way of giving local party members a meaningful say in the selection of Senate candidates," he said. "If we are to renew and rebuild the Labor Party, we must rebuild as a membership-based party, not a faction-based one." Senior Labor source said Mr Shorten had been "standing very, very still" on his pledge. Reforms proposed by the national executive recommend endorsing some of the Rudd reforms to protect a Labor leader in caucus but do not mention Senate preselections. The model to be pushed by the Left goes beyond the Faulkner, Carr, Bracks report, which found democratising the Senate selection process would be unachievable.

The Right wants to leave any reform to individual state branches to decide, but some figures from the Right have spoken publicly in favour of a direct voting system, including shadow treasurer Chris Bowen. Tim Ayres, NSW secretary of the Left-aligned Australian Manufacturing Workers' Union, said there would be a lot of talk inside the party to try to lock in agreement at conference. "We don't want to miss the opportunity this national conference presents to land a more modern, more democratic Labor Party," he said. Reform advocate Darcy Byrne said: "The days of party members being prevented from voting in Senate preselections must come to an end, and the progressive wing of the party must lead the way.



"If recent history has taught us anything it's that allowing Labor's Senate candidates to be selected through archaic methods is a turn-off for modern voters." A spokesman for Mr Shorten did not address the question of Senate preselection reform directly, saying that he "remains absolutely committed to rebuilding and growing the Labor Party".

"Bill Shorten will continue to prosecute the case for Labor to rebuild as a more democratic, more inclusive, more representative party," he said. Follow us on Twitter