Backers of Julia Gillard are staring down the latest threat from supporters of Kevin Rudd, challenging him to make a move against the prime minister.

“The ball’s in Mr Rudd’s court,” cabinet minister Greg Combet told Sky News on Wednesday, adding senior ministers would not tap Gillard on the shoulder.

“The prime minister is not going to stand down.”

Combet was responding to reports that backers of Rudd are gathering the names of at least 55 MPs who are prepared to support the former prime minister in a leadership ballot.

Any move against Gillard will first require a petition, signed by at least a third of the caucus, for a special meeting.

A separate ballot would be required for a leadership spill.

Another cabinet minister and Gillard backer, Craig Emerson, dismissed reports that vote would be a “show of hands”, saying it “never happened before and never would again”.

Asked whether a petition for a special caucus meeting was being circulated amongst Labor MPs, Emerson told Sky News: “I have no sense of that at all.”

Parliamentary secretary Amanda Rishworth says she isn’t aware of any petition for a special caucus meeting.

“There’s no process for change underway,” she told reporters in Canberra.

Gillard’s claim on the leadership could be saved by the independent MPs who back her minority government on the floor of parliament.

Tony Windsor reportedly has told Gillard that he will not back Rudd’s return as prime minister.

In the event Rudd became prime minister, the MP said he would support a no-confidence motion against the government, the Seven Network said.

Labor MP Ed Husic, a Rudd backer, said it was not helpful for people outside Labor to “pour fuel on the fire”.

But he played down any move against Gillard.

Nationals Senate leader Barnaby Joyce also poured scorn on the latest developments.

“It’s like watching a cat play with a ball of string,” he told ABC Radio.

Rudd is under pressure from his caucus supporters to make a move on the prime minister in the dying days of the current parliament, which is due to rise for the last time on Friday, ahead of the September 14 election.