Senator Dean Smith will push the government for the policy, after obtaining research that shows only 864 full-time regular Army soldiers, out of the nearly 30,000 personnel nationwide, are based in WA.
Senator Smith said he was surprised to learn that South Australia has 70 per cent more personnel than WA, despite its smaller coastline and its situation on the southern part of the continent.
"The research shows that Western Australia has the second-lowest permanent Army force, compared to Queensland with 12,394 and South Australia with 1,476," Senator Smith said.
"The only state or territory with less of an Army presence than WA is Tasmania, which has less than 70 personnel. This is despite the fact that 56 per cent of Australia’s coastline is astride to the Indian Ocean compared to just 27 per cent for the Pacific Ocean and 17 per cent for the Southern Ocean."
The senator said the strategic significance of having more personnel is emphasised not only by its geographical location, but also by the state's abundance of natural resources.
"WA accounts for 78 per cent of Australia’s crude oil, 92 per cent of natural gas, 49 per cent of global iron ore production and some of the world’s largest reserves of lithium," he said.
"It is an unfortunate fact that over the past four decades, the regular Army presence in WA has been greatly diminished."
The senator will call for an inquiry into the merits of a two-armies policy, noting that an unofficial Two Army Policy was implemented during World War II and by December 1942, of 23 brigades deployed throughout Australia, six were based near Perth, which amounted to 26 per cent of Australia’s combat forces.
"In 2018, it is my intention to call for a Senate inquiry to establish a Two Army Policy where a significant proportion of regular Army personnel are stationed in Western Australia as well as the east coast," Senator Smith said.
"Such an inquiry is timely given the volatility in the Indian Ocean region and the potential challenges that our nation may face in the future."
The senator said he also understood the WA-based reserve unit, 13th Brigade, was now commanded by an Adelaide-based Army Reserve brigadier who will visit WA on a fly-in, fly-out basis for at least one year.
"The scaling back of the regular Army presence in WA has occurred at a time when much of the global economic and political instability is taking place in the Indian Ocean region where our personnel have been regularly deployed in recent years to locations such as Iraq and Afghanistan," he said.
A review of the Australian Defence Force's structure of military units was previously undertaken under the Gillard government by then defence minister Stephen Smith, also of WA.
Upon completion of the review, the Department of Defence committed to a major exercise in WA’s north each year, flying in elements of east coast army units to show the military could mobilise quickly to meet any threat to the west coast.