The number of motor vehicles stolen in WA has jumped almost 50 per cent in four years, with more than 9000 cars, motorcycles and scooters taken last year.
The WA Police annual report shows vehicle thefts rose 12.5 per cent to 9205 in 2012-13 and burglary rates remained "relatively high" for the past three years but fewer crimes were resolved.
The failure to meet targeted "sanction rates" - an offender being caught or inquiries discontinued - for crimes against people (such as assaults and robberies), crimes against property (such as burglaries) and drug trafficking comes as police face increased demand on resources.
Commissioner Karl O'Callaghan said compared with the WA population increase, crime rates were almost unchanged.
"But it's obviously creating a lot of pressure for police," he said.
The number of triple-zero calls has risen 10 per cent since 2010-11 to 270,364 last year and calls for assistance to 131 444 increased 12.9 per cent from 2011-12 to 775,944 last year.
Despite that, operators answered more calls within their 20-second target than the previous year.
Officers also responded to life-threatening priority 1 and 2 calls within the target of nine minutes but on average responded to lower priority calls in 31 minutes, above the 25-minute target.
National Motor Vehicle Theft Reduction Council executive director Ray Carroll said much of the vehicle theft rise, particularly in 2012-13, involved motorcycles and scooters.
The 47 per cent rise in vehicle crime in recent years also came after a decade of falling rates.
In the late 1990s, WA had a serious car theft problem almost double the national rate but immobilisers brought the rate down for almost a decade to under the national average. The vehicle theft rate was now just above average.
The annual report also shows 27,400 reported burglaries in 2012-13, 27,362 the previous financial year and 26,618 in 2010-11.
But non-domestic assaults fell 151 to 11,933 last year and are down 17.3 per cent since 2008-09.
Mr O'Callaghan said so far this financial year, burglary and other crime rates were down in most of the metropolitan area.Shadow police minister Michelle Roberts said the statistics showed the police force was under-resourced.