THE effectiveness and legality of the Drugalyser - launched in the Western Cape last week - has been called into question by a local attorney and the Automobile Association.

Marius de Kock, a local attorney, said the idea that it is within the power of the police to do the testing of drugs "within the law is ludicrous".

"That MEC (Patrick) McKenzie can spend this much money without first talking to the Director of Public Prosecutions is laughable. The police have been coercing people into taking this test. It is an invasion of privacy. The fact is that they know that the test is not admissible, but expressly choose not to tell the public. If the public knew that they could refuse," De Kock said.

A drug driving report put together by the company manufacturing the device showed that a high number of Cape Town motorists pulled over at roadblocks tested positive for drugs. The tests were carried out at roadblocks between April and November.

But Automobile Association (AA) spokesperson Gary Ronald said there was no in-depth research proving that drug driving was a problem like drunk driving.

"It's because it's an illegal activity. With alcohol, we've got a good idea because of data collected over years. To properly test for drugs you need a full toxicology and this could be thousands of rands. And there's also the question of how much drugs are in your system (at the time of the screening). There might be residual, but you're not spaced out. It won't stand in court, but that might come with time," Ronald said.

He said the AA supported the idea, however.

Trimega Diagnostics managing director Avi Lasarow said the Drugalyser was very accurate and the technology was in use in nine countries.

In its drug driving report, Trimega Diagnositics said it was clear from its review of existing legislation "that urgent amendments were required to address roadside testing for drugs (as well as) alcohol".

[email protected]