A plywood train is sitting in Perth's CBD, part of a council protest against state government plans to run the real thing down the middle of the city's shopping malls.

The $100,000, 42-metre-long scale model of the dual light-rail line popped up overnight.

Lisa Scaffidi tweeted this picture of the pywood trains, with the hastag #dontmaxthemalls Credit:@LisaScafPerthLM

And in an inflammatory move, Perth Lord Mayor Lisa Scaffidi says the model will stay in place for a week to illustrate the inconvenience and potential danger of the plan.

"Once our malls are lost they are lost forever, and we want a city that is welcoming to people," Ms Scaffidi said.