The Age understands documents related to Mr Mirabella’s role in the company have been circulated to some delegates who are set to ask questions over his links when candidates address the preselection forum in six days’ time.
Tim Hossack, a former director of Global Enviro and shareholder, said the shell company had never traded and ASIC had only commenced strike-off action because “one of the blokes forgot to pay the bill”.
“That has been paid now. End of story. It shouldn’t be misconstrued into anything it isn’t,” Mr Hossack said.
Ms Henderson was the early frontrunner in the contest off the back of high-profile endorsements from Prime Minister Scott Morrison and Treasurer Josh Frydenberg.
But the race has deteriorated into a proxy factional war, with a rear-guard action of branch members now rallying behind Mr Mirabella.
He is understood to have the support of between 220 and 250 – about 45 per cent – of the 550 delegates who will vote at Caulfield Racecourse.
His backers believe the Senate vacancy was “orchestrated” to return Ms Henderson to Parliament after she narrowly lost her Geelong-based seat to Labor in May and say her strong support from Canberra has alienated the party’s grassroots membership who regard it as their right to choose Senator Fifield’s successor.
Ms Henderson is estimated to have between 150 to 170 votes, with both campaigns likely to rely on winning support from other candidates as they drop out of the race.
Conservative candidates Kyle Hoppitt and Inga Peulich are estimated to have about 50 votes each.
Other candidates include Chris Crewther, mental health advocate John MacIsaac and African-born public health expert and academic Mimmie Watts.
Ms Henderson, who is based in Barwon Heads, is understood to be struggling to win support from many regional party delegates because of her previous outspoken opposition to the live sheep export industry during the last parliament.
Conservative factions are also struggling to back her because she was among a group of MPs who voted to oust former PM Tony Abbott and install Malcolm Turnbull in August 2015.
Mr Mirabella’s backers are blaming factions traditionally aligned with former party president Michael Kroger for the attacks on him, which they say shows “they are becoming increasingly desperate”.
“They went out early for Sarah and now they are doing everything they can not to embarrass themselves and the PM who they appear to have assured she would win,” one Liberal said.
Those close to Ms Henderson say she is not reliant on Mr Kroger’s support in the race and has “broad endorsements” from across the party, including former premiers Jeff Kennett, Ted Baillieu and Denis Napthine.
Neither Ms Henderson nor Mr Mirabella would comment on Sunday, citing party rules which prevent candidates speaking publicly during a preselection contest.
Rob Harris is the National Affairs Editor for The Sydney Morning Herald and The Age, based at Parliament House in Canberra
Samantha is the The Age’s CBD columnist. She recently covered Victorian and NSW politics and business for News Corp, and previously worked for the Australian Financial Review.