Soaring world demand for steel could more than double the cost of building wind farm towers in Portland next year.

Forecast rises for Australian steel would mean a $70 million bill for Portland-based Keppel Prince Engineering.

Flat plate steel which cost $1200 a tonne early this year is tipped to hit $2800 a tonne in 2009.

Consumer goods and construction industries across the board will be hit by the massive increase.

Keppel Prince, a large manufacturer of huge steel towers for wind farms, expects to use 18,000 tonnes of flat plate steel this year. The company expects to use 25,000 tonnes in 2009.

General manager Steve Garner said steel prices were a concern.

"It's a volatile market and (it's) hard to get a reliable quote on steel prices more than 30 days ahead," he said.

"We are tendering on jobs for early next year when they forecast Australian steel could reach $2800 a tonne. Therefore we are looking at all options, including importing steel from China."

Mr Garner said Chinese steel could be imported for about $1800 a tonne, but overseas supply was sometimes less reliable.

"We believe we can still be competitive in the tender process for wind towers," he said.

The company employs 520 staff for wind farms, aluminium smelter maintenance and a variety of steel fabrication work.

This year it will produce 100 towers for wind farms across Australia.

Next year Mr Garner anticipates 150 towers in the production line.

Pacific Hydro, which has four wind farm projects, said rising steel costs would not cause plans to be delayed.

It has 29 towers at Cape Bridgewater which are being commissioned for service and has started construction of a project at Cape Nelson south.

Final layouts of a farm at Cape Sir William Grant are being prepared and planning for another at Cape Nelson north is expected to soon be finalised.