The Labor leader, Bill Shorten, has issued a public warning to factional powerbrokers against targeting sitting MPs in his home state, declaring that with state and federal contests looming the ALP needs stability.

In a public signal that he will back referring all Victorian preselections to Labor’s national executive for endorsement and in some cases deliberation and decision, Shorten told reporters on Tuesday he wanted “a period of stability for my MPs”.

Factional powerbrokers in Victoria are at loggerheads over whether preselections in the state require federal intervention. The issue was meant to be discussed at a meeting of the Victorian party admin committee on Wednesday night but party sources say that meeting has now been deferred.

At the last meeting of the state’s admin committee, party sources say the rightwing powerbroker Adem Somyurek tried to head off the push to have preselections go to the national executive but the committee was deadlocked.

While a final decision has not yet been taken, senior party figures insist the Labor leader has given private undertakings to key players that the national executive will step in, despite fierce resistance from the Somyurek group.

The current power struggle relates to a bitter factional realignment that has been playing out on Shorten’s home turf for more than six months.

The Somyurek group wants to overturn a stability pact negotiated between the right faction powerbroker and former Labor frontbencher Steven Conroy and the veteran leftwinger Kim Carr’s socialist left faction. That agreement mapped out a plan for state and federal preselections up to 2022.

The Carr/Conroy group is resisting the power realignment and has been pushing to have preselections kicked to the national executive since late last year with the objective of enforcing the stability pact and holding out the insurgents.

Supporters of intervention say rank-and-file ballots will threaten sitting MPs given the Somyurek group is looking to consolidate its position, but the Somyurek camp says sitting members won’t be targeted because the right faction agreed a week ago not to go after incumbents.

With powerbrokers at odds in the state, recent boundary redistributions have changed the electoral terrain in Victoria, creating new seats and adjusting boundaries, and the recent departures telegraphed by the long-serving Labor MPs Jenny Macklin and Michael Danby has put more seats in play, intensifying the local warfare.

Shorten told reporters on Tuesday he would leave Victorian preselections to the Victorian Labor party and its officials but “one thing I will make clear, though, both internally and externally: I back my sitting MPs”.

“If I have got sitting members who want to keep contributing, I want them on the front line,” he said. “What I will offer is a period of stability for my MPs ... I will make sure I protect my sitting MPs.”