Political commentators say largely unknown Labor Party factional strongmen have shown their control of the Labor Caucus by engineering the political demise of Kevin Rudd.

Mr Rudd was ousted by his deputy Julia Gillard in an unopposed leadership spill after it became clear that he had no chance of marshalling the numbers to prevail in a contested leadership vote.

Some of the strongmen behind his demise are union bosses, while others have made the transition into Parliament as members and senators.

Apart from wielding power, there is one thing that they have in common: they are largely unknown to the Australian public.

David Feeney, Mark Arbib, Bill Shorten, Bill Ludwig, Karl Bitar, and Don Farrell are hardly household names, yet they hold sway within the Labor ranks.

Political commentator Professor Ross Fitzgerald says the Labor Caucus largely reflects the views of the factional strongmen.

"The factions these days in the main reflect the Caucus," he said.

"But in terms of the exercise of power, when push comes to shove, the factions, and especially the right faction, wields tremendous power in the Australian Labor Party federally and in most states.

"For Kevin Rudd to say as he did that he wanted to break the power of the factions is laughable.

"I would have thought this is the factions' revenge. He went down like a house of cards."

Professor Fitzgerald earned his spurs in Queensland, home to Mr Rudd and Ms Gillard's new deputy Wayne Swan.

But the state is also the power base of Senator Joe Ludwig and his father, Australian Workers Union (AWU) national president Bill Ludwig.

The Ludwigs control the AWU along with the AWU's shining light in Federal Parliament, another Rudd coup plotter, Victorian MP Bill Shorten.

Professor Fitzgerald says Mr Shorten, along with fellow strongman Mark Arbib, will do extremely well out of the overthrow of Mr Rudd.

The World Today has spoken to former premiers, MPs and Labor stalwarts, who all agree that Mr Rudd suffered at the power of the factions.

They also say that internal polling conducted by the ALP showed the devastating effect Mr Rudd would have on the Government's election prospects if he remained leader.

One Labor source says the internal polling reflected a view much worse than Newspoll's own published poll.

The source says that when faced with the evidence the heavyweights came together at the beginning of this week to try and convince Julia Gillard she had to challenge.

While the right wing of the party would have preferred to push one of their own into the top job there was simply no alternative but to tap the left-winger Ms Gillard on the shoulder.

One insider says the move to oust Mr Rudd only had one focus, to ensure Labor won the next election.

However, another source says there is also a sense of irony, as many of those same factional bosses who helped oust Rudd had also given him advice that helped undo his popularity with voters.

The source says it was not just Mr Rudd who over promised and under-delivered, but it was Mr Rudd who paid the political price.