NSW's health minister has rejected Labor's push to swiftly decriminalise cannabis for the chronically ill, arguing the move is not yet backed by clinical experts.

The state opposition plans to introduce a bill to parliament this week which would allow medically-certified sufferers to carry small amounts of cannabis up to 15 grams.

Labor leader Luke Foley says people with serious or terminal conditions should not be treated like criminals for trying to ease their pain.

But Health Minister Brad Hazzard has accused Mr Foley of "taking advantage of vulnerable people" by politicising the issue.

"No clinical expert would actually endorse what (Mr Foley) is saying," Mr Hazzard told question time on Tuesday.

NSW has already begun trialling medicinal cannabis for cancer sufferers and children with epilepsy.

The government needed to make sure the "gold-plated, customised, randomised trials" get the process right to minimise the potential risks, Mr Hazzard said.

"They are also making sure that people who do get the benefit of this medication will do so in a safe environment."

Mr Hazzard later told AAP that there were very few cannabis products globally available that have been formally assessed for safety and efficacy by a medicines regulator.

"What Labor also seems to forget is that it is already lawful for patients to use legally produced and prescribed medicinal cannabis products in NSW," he said.

Lucy Haslam, the mother of 25-year-old Dan Haslam who went public with his cannabis use to treat his terminal cancer, is pushing the government to speed up the trials.

The high-profile campaigner argues patients are facing too many hurdles finding doctors who are authorised prescribers.

Mr Hazzard will meet with Ms Haslam on Wednesday to discuss the issue.

"The NSW government recognises the need to better understand the therapeutic potential for cannabis-based medicines and we are conducting world-first clinical trials to do just that," Mr Hazzard said.

"But the reality is clinical trials take time ... and we would be negligent in our responsibilities if we rushed through changes without evidence from those trials to inform our decision making."