WesTrac owner Seven Group expects its earnings to fall by more than a third in the year ahead as a downturn in the mining sector causes a slump in machinery sales.
The industrials and media group's gloomy outlook for the 2013/14 financial year sent its share price tumbling by more than seven per cent
That was despite a profit of $486 million in the 2012/13 financial year, almost triple its $177 million result for the previous year.
The forward order book for WesTrac, a distributor of earth moving equipment, is now much smaller because of a slowdown in mining investment, Seven Group said.
The downturn was affecting operations in NSW, which are tied to the struggling coal industry, chief executive Don Voelte said.
"WesTrac Western Australia is going okay, but we do see pressure on the mining managers to maximise their cash flow," Mr Voelte told analysts on Tuesday.
"NSW is probably even a little bit worse than even we might have thought."
Mr Voelte said the group would review its capital expenditure and costs to meet the changing market demands for mining and industrial services products.
Seven Group also holds a major stake in Seven West Media and Coates Hire.
Given the uncertain outlook for both the mining and media industries, the company expects its profit to fall in 2013/14.
Wilson HTM analyst Peter Esho said the downgrades signified just how weak things were outside the media business.
"It brings into question the appropriateness of bringing WesTrac into the stock and whether that was in the best interest of all Seven Group shareholders," Mr Esho said.
"It's now one of the key drags in the earnings and it isn't expected to improve for a couple of years."
Seven Group's 2012/13 profit was driven by a strong first half performance from WesTrac.
It was also boosted by $90 million worth of one off items, including a $50 million gain from the sale of the company's stake in Consolidated Media for $491 million.
Seven Group shares were down 60 cents, or 7.8 per cent, at $7.10 at 1522 AEST.