The Enquirer understands that the concrete specialist withdrew from sites, apart from a handful of London jobs, on Friday.
The move follows a turbulent few weeks for the firm after it filed a notice of intention to appoint an administrator at its contracting division earlier this month.
Accountant KPMG was named as a potential administrator of PC Harrington Contractors Ltd.
Harrington is understood to be continuing work on its contract for Mace at the Nova development in Victoria.
Harrington senior staff are believed to have met with Mace directors late last week to discuss the firm’s situation.
A Mace spokesperson said: “We continue to work with PC Harrington on current projects.”
A union source said: “Workers on a number of jobs were stood down on Friday while talks continue about the company.”
Harrington has been raising funds since the start of this year when its HTC Plant division sold its hoist operation to Dutch specialist Reco.
The firm has also been pursuing a sale of its HTC tower crane division.
Wolffkran is believed to be a potential buyer but the German manufacturer is understood to have gone cool on the deal.
PC Harrington declined to comment.