Australia's accountants are warning sluggish productivity levels are threatening the nation's living standards, economic growth and competitiveness.CPA Australia, the peak professional accounting body, says the federal government must take steps now to lift productivity levels instead of kicking the can down the street."Australia is running out of time. If productivity continues to stagnate, living standards will go backwards and the economy will struggle to sustain growth," CPA business and investment lead Gavan Ord said.READ MORE: NAB chief warns living standards