The lack of facilities along Forrest Highway has caused motorists to often run out of fuel and be forced to urinate and change baby nappies on the side of the road.
Liberal MP Murray Cowper has described the highway as "the busiest, most unserviced, long stretch of highway in the nation". There are no roadside facilities for most of the 110km journey between Perth and Lake Clifton, along Kwinana Freeway and Forrest Highway.
And though Kwinana Freeway offers several opportunities for motorists to turn off to access facilities - such as Canning Highway and Beeliar Drive - there are few similar opportunities on Forrest Highway.
Mr Cowper, the member for Murray-Wellington, wants Main Roads to change its stance towards the building of a roadhouse on the highway so that motorists can get roadside access to fuel, food and toilets.
He has called on Premier Colin Barnett to intervene and "cut some of the mounting bureaucratic red tape" that was preventing local developers from building the necessary facilities.
Local landowner Eric Walmsley, whose property was cut in half by the construction of the highway, is prepared to build a roadhouse at Herron Point Road, 10km north of Lake Clifton.
But he has been told by Main Roads it will not approve the plan unless he is prepared to build a second, identical roadhouse on the other side of the highway.
"Drivers leave Perth expecting to come across a roadhouse," Mr Walmsley said. "When they don't, they get into trouble.
"At least once a week, we get people coming to our door because they have run out of fuel or have broken down. We have also had people turn into our driveway to relieve the call of nature. The worse thing is the litter that some of them leave behind - things like used nappies, old tyres, general rubbish."
Mr Cowper said there was an opportunity for private investors - and not taxpayers - to provide essential services on the highway.
A spokeswoman for Transport Minister Troy Buswell said establishing roadside facilities on Kwinana Freeway and Forrest Highway was "a complex process" that was taking longer than expected.
"These are private commercial developments," she said.
"While there are some planning issues for the proponents to resolve, one of the key hurdles in getting the sites developed is the significant up-front capital cost."