Some US companies are concerned about a potential terrorist attack targeting oil and gas developments off the WA coast.
PerthNow reports WA lawmaker Alan Eggleston told a Senate committee several companies had approached him voicing concern about security in the region.
"They say their American investors are particularly concerned that perhaps the defence of, and the protection for, these facilities is not quite what it could be," he said.
"A lot of our American investors are concerned about the possibility of terrorism."
Earlier this year Australian Defence Force planners urged the military to build a strong presence in Australia's north to guard resource projects.
The call was echoed by the Federal Opposition, which said in 20 years time Australia would be providing between ten and 20 per cent of China's energy.
"We need a strong, capable navy focused around force element groups that are a deterrent — namely submarines," Opposition defence spokesperson David Johnson said.