The legislation, passed unanimously on Wednesday night, opened up a legitimate pathway for patients with certain types of illness to access the treatment.

Regulatory changes introduced last year allowed individuals to apply for treatment but only one person had been approved to date.

A Logan family's "long and at times frustrating" battle to get treatment for their son was highlighted in the lead-up to the bill's passage.

Lindsay Carter's inoperable brain tumour, which triggered violent seizures, prompted the family to travel to Washington for cannabis treatment before he was approved for treatment in Queensland last year.

"The treatment in America proved a huge success for Lindsay and allowed him to live his normal life like a teenager again," Child Safety Minister and Waterford MP Shannon Fentiman told Parliament.

"When Lindsay returned to Australia without the medication, the seizures came back.

"If his family were to try to access the treatment that they know works, they would be treated as criminals under our laws. It just does not make sense.

"We have to put ourselves in Lindsay's and (his mother) Lanai's shoes to understand how frustrating it would be to have a drug which works and stops seizures only available in countries thousands of kilometres away and at very huge expense."

The new legislation would give doctors, particularly specialists such as oncologists, paediatric neurologists and those involved with palliative care, the chance to apply to prescribe the drug.

It would remain illegal without the appropriate approvals but could be prescribed to treat problems such as chemotherapy-induced nausea and epilepsy.

Australian Medical Association Queensland president Dr Chris Zappala said he saw the potential value in medicinal cannabis but there needed to be a stronger regulatory framework.

"We still do not have enough evidence about the long term effects and we need to understand not just the potential benefits but also the risks, " he said.

" There is insufficient data for us to know yet whether we may inadvertently being doing harm in a poorly conceived effort to help patients.

"This is why we normally insist on a certain level of evidence before therapies are approved – the same standard must apply to medicinal cannabis. "

LNP Member for Buderim Steve Dickson said it was possibly the "most important bill we see before this House this year".

Premier Annastacia Palaszczuk, who has previously cited the plight of families such as the Carters as a key motivator in moving on medical cannabis, said it was a milestone for tireless campaigners.

The government labelled the laws Australia's "most progressive".

"My government has been moved by the stories of families with young children with epilepsy, suffering life-threatening seizures, and what they have to go through on a daily basis," she said.

Health Consumers Queensland chair Mark Tucker-Evans also welcomed the bill's passage.

The laws are expected to take effect within a few months but drug supply will still require approval from the federal Therapeutic Goods Administration.

The bill, amended to largely reflect committee recommendations made earlier this month, also formalised the process for individuals to apply for cannabis treatment, replacing the regulatory change.

The Lady Cilento Hospital is involved in a government-sponsored medicinal cannabis clinical trial.