Police have added a battery of tests to their armoury in a renewed crackdown on the city's drug-drivers.
From Thursday, officers will be able to compel drivers suspected of being under the influence of narcotics to give urine and blood samples if they fail a new five-part impairment test.
The changes follow 18 months of negotiations with lawmakers and come just weeks after the driver of a red-top minibus was arrested for drug-driving on suspicion of taking ketamine.
Superintendent Shylock Wong Yiu-ming said the tests were expected to be 95 per cent accurate and make it easier to determine whether motorists were under the influence of drugs.
They are based on models in Australia, Britain, the United States and Canada. A total of 200 traffic police officers have been trained to conduct them, with plans to expand that number to 1,200 officers. Wong said the officers empowered to run the tests were well qualified and would only apply them to drivers 'under reasonable suspicion'.
The police crackdown will focus on six illicit drugs: heroin, ketamine, Ice, cannabis, cocaine and Ecstasy.