ALP president Mark Butler has lashed out at the "backroom buffoonery" of the party's factional warlords, accusing them of blocking internal reforms and leaving Labor's members with fewer rights than in any comparable movement in the world.

In an extraordinary speech to mark the imminent end of his tenure as president, Mr Butler has declared that given its dwindling membership Labor is barely "treading water" and can no longer credibly claim to be a mass-membership party.

Calling on the party to finally "grasp the nettle" of reform at this year's ALP National Conference – to be held in Adelaide in July – Mr Butler said his efforts to give the rank and file more say had been frustrated by factional bosses.

"I'm sorry to say that ours remains a party that gives ordinary members fewer rights than any other Labor or Social Democratic Party I can think of," Mr Butler, who serves on Bill Shorten's frontbench as spokesman for climate change and energy, said in the speech to the Victorian Fabian Society on Monday.