The Prime Minister, John Howard, has warned his MPs not to accept help from the Exclusive Brethren, and Kevin Rudd has refused their requests to meet him.
Revelations of the religious sect's covert political activism, the funding of their schools and attempts to influence the Family Court have made the Brethren political poison.
Sources have said that the Mr Howard's message filtered out via NSW Senator Bill Heffernan that MPs were not to accept help or donations from the group, as public suspicion of their influence on politics grows.
Neither Mr Howard nor Senator Heffernan responded to queries yesterday.
New evidence from 2005 shows that the Brethren viewed the relationship with the Prime Minister as close.
"Howard is a born economic manager," gushed the Exclusive Brethren's world leader, Bruce Hales, just months after the 2004 election in which Brethren-funded advertising helped the Liberals. "And he has studied it, and studied it, and studied it and, as we told him the other day, he has the economy by the throat," he told a seminar for his flock in Sydney in February 2005.
"And that is basically why he's got back into power, plus his Christian values which many people won't admit that they like, but underneath they like."
The sources said that the Brethren had not only funded political advertising on behalf of the Liberal Party, but had also provided manpower to drop Liberal leaflets in letterboxes.
Documents obtained by the Tasmanian anti-hate campaigner Martine Delaney show the state party was invoiced for Brethren advertisements, and a Tasmanian newspaper has reported that Brethren members were given suggested talking points, or even scripts, by Liberal officials to guide their telephone canvassing and political comment in the lead-up to the last Tasmanian election.
Mr Howard has admitted to meeting the Brethren, but will provide no detail of the discussion, but approaches by Brethren members for a meeting with Mr Rudd have been turned down or ignored, Labor sources say.
Labor now seems almost certain to support a motion by the Greens leader, Bob Brown, for a Senate inquiry into the Brethren's activities.
A spokesman for Mr Rudd said yesterday: "We'll look at it constructively, and if we don't have any problem with it, we'll support it."
The Australian Democrats senator Andrew Murray said the party would consider supporting a Senate inquiry.
When Senator Brown moved a similar motion last year, the Democrats and Labor opposed it.
A Brethren spokesman said Senator Brown was indulging in a "witch hunt," and that nothing in his case justified an inquiry.
"We believe that this motion is just payback for the Brethren's involvement in questioning Green policy in Tasmania," the spokesman said.
"The political campaign in Tasmania was in fact a few individual members, who may have been overenthusiastic and naive, but now Senator Brown is trying to punish the whole Brethren movement."
The spokesman said the Brethren abided by Family Court orders. He denied the sect discriminate against women, and said it used public money for schools only. In accordance with the legislation and funding guidelines, all accounts were audited, the spokesman said.