Nearly 1000 doctors, nurses, addiction specialists and allied health professionals are pressuring the Senate crossbench to reject the Turnbull government's plan to drug-test welfare recipients.

The medical professionals – who have more than 20,000 years combined practical experience – have signed an open letter saying there is no evidence to suggest the policy will work and will not help people with drug addictions.

"Not only will this trial fail to reduce drugs, it will increase crime and drive social division. If Parliament wants to reduce the social harms of drug and alcohol addiction, it should spend the money on proven, frontline treatment services that work," Dr Marianne Jauncey​, a public health physician and a member of the Australasian Professional Society on Alcohol and Other Drugs, said.

"We're calling on Parliament to listen to the expert advice of addiction medicine specialists, drug and alcohol nurses, social workers, clinical psychologists, public health academics and trauma counsellors. We are drawing on our experience when we say that this trial is ineffective, counterproductive and ignores evidence."