The theft of numberplates for use in robberies, burglaries and fuel drive-offs has continued to rocket despite police efforts to stem the surge, with almost 4500 stolen in the past year alone.
Department of Transport figures reveal 4474 sets of numberplates were stolen from WA cars and motorcycles last year - more than 12 a day and 355 more than in 2012.
The number of plates stolen last year is almost double the amount stolen in 2010.
Numberplates fitted with standard screws can be removed easily with a screwdriver within minutes.
WA Police last year held workshops across the metropolitan area to help motorists fit "anti-theft screws" to their vehicles to prevent the theft of numberplates.
Despite this, thefts have continued to rise.
The stolen plates are often used in fuel drive-offs - a crime the body representing service stations, the Motor Trade Association of WA, has identified as the industry's biggest problem.
It says the crime is costing petrol retailers millions of dollars a year.
A police spokesman said evidence and intelligence suggested numberplates were used to commit crimes such as fuel drive-offs, robberies and burglaries.
He said numberplates were being stolen from vehicles and replaced with numberplates from stolen vehicles.
"A theory behind this is that individuals won't notice their numberplates missing and therefore not report the theft to police," the spokesman said.
"Ultimately, this gives offenders time to use the non-reported stolen numberplates to avoid detection by police."
The stolen plates are often found by police before their owners realise they are gone.
The MTAWA has previously called for an automatic $500 fine for fuel thieves to effectively remove the excuse of "forgetting" to pay for fuel, which makes it difficult for police to prosecute.
Last year, association chief executive Stephen Moir said false numberplates made it even harder to track down thieves.
He said fuel drive-offs became more frequent when fuel prices rose or during tough economic times and were not confined to low socio-economic areas.