``The look on some people's faces when we said they'd been selected for a random drug test was surprising,'' Sergeant Grant Bucknell said.

About 1400 people were pulled over and 348 of them were also tested for drugs.

Sergeant Bucknell, from Macquarie Fields Highway Patrol, said five people returned a positive blood alcohol reading while six returned positive readings for drugs.

``This means that about one in 50 people tested positive to drugs, which makes it a bigger problem than alcohol,'' he said.

``The drug test takes about five minutes and it's a saliva swipe that people have to slide in their mouths.

``If their test comes out positive then they are given a secondary test, like in a breath test, and we observe the results from that if it's still positive then the sample is taken to an analytical laboratory and from there, that's when the charges are laid.''

The drug test van was set up on Friday and Saturday nights.

``We're hoping to get the drug testing van back again soon,'' Sergeant Bucknell said.

``I have requested that we get it back again in November as well.

``The reason why we probably got more people on the Friday and Saturday was because that's when people go to parties.

``My message to people is to watch this space because it's coming back.''