The chairman of construction company, Macmahon, has apologised to shareholders for a recent downgrade in earnings forecast.
The company halved its earning forecast for the 2012/2013 financial year.
It had forecast earnings for that period of more than $70 million but now says it is likely to earn between $20 to $40 million, blaming continued market volatility and uncertainty about future projects for the fall.
It has also been affected by management problems with its rail earthworks project at the Hope Downs mine in the Pilbara.
The mine is a joint venture between Rio Tinto and Gina Rinehart's Hancock Prospecting.
The company's longstanding chief executive, Nick Bowen, resigned as a result of the announcement.
Chairman Ken Scott-Mackenzie says the entire board is extremely disappointed by the downgrade and is focused on assuring it rebuilds shareholder confidence in the company.
He says the company is undertaking a number of measures to achieve this, including a review of its operating expenditure and an evaluation of its construction business.
He will outline the changes at the company's annual general meeting on Friday.