The 53-year-old is not trying to get high, but illegally uses medicinal marijuana to deal with the debilitating pain he suffers after a massive operation to remove a football-sized tumour from his spine.

Mr Lawrence has organised the Wollongong Medicinal Cannabis Symposium on Saturday to draw attention to medical use of cannabis. And he is calling on the NSW government to extend its clinical trials in the area.

Guest speakers at the event will include an Australian father facing charges for cultivating the cannabis he uses to help his epileptic daughter, and a Sydney doctor deregistered for recommending and supplying cannabis to patients.

Mr Lawrence was diagnosed with a rare spinal tumour in 2010. He had three vertebrae removed during his 43-hour life-saving operation and five of his ribs, a leg bone and 60 pieces of titanium were used to rebuild his spine.

Radiotherapy and other treatments did not stop tumours returning. A range of legal painkillers did nothing to curb his chronic pain, and caused serious side effects.

Just over a year ago, after a bad experience with painkillers, he gave them up altogether and turned to marijuana.

‘‘I can feel all the titanium structures in me but what hurts the most is where the bones were taken and the muscles had to be reattached, but they no longer do the same job they were designed to do,’’ Mr Lawrence said.

‘‘The painkillers I was taking were having such a negative effect on my health – once every month they’d build up in my system and I’d spend 12 to 36 hours violently ill, sweating, vomiting and shaking.

‘‘The last time that happened my partner was at work and I was unable to get out of bed to take my son to school, and he had to look after me.

‘‘I stopped taking painkillers that day.’’

Mr Lawrence said his quality of life had vastly improved since that day, and his latest scans show no further growth in his tumours.

‘‘The tumours are not aggressive but will kill me slowly unless I find something to stop them in their tracks,’’ he said.

‘‘My neurosurgeon and oncologist agree with my use of medicinal marijuana up to a point, as everything else that’s been tried has not been successful.’’

Australia’s first medical cannabis trial for terminally ill adults would take place in Newcastle, Premier Mike Baird announced in July.

The trial is part of a $9-million commitment by the NSW government to support medical cannabis clinical trials across the state. It will evaluate two types of cannabis products: vaporised leaf and pharmaceutical.

Mr Lawrence welcomed the trials, although he said it was a case of too little, too late.

‘‘Medicinal marijuana is being used successfully in many countries, including Israel and Canada, and Australia is being left behind,’’ he said.

‘‘It doesn’t need to be tested, it needs to be used now. We have people who are suffering now, who are going to die before politicians make a decision on this. And that’s unacceptable.’’

The public symposium will be held at Woonona Bulli RSL, from 11am to 4.30pm on Saturday.

An Australian father is facing charges for cultivating the cannabis he claims has saved his little girl’s life.

The father, who did not want to be named, will speak via video-link at a medicinal marijuana symposium in the Illawarra on Saturday.

He told the Mercury that since he started treating his three-year-old daughter who has epilepsy with cannabis oil, her seizures have dramatically reduced.

‘‘My daughter also has cerebral palsy, is visually impaired and partially deaf,’’ he said.

‘‘She used to have up to 100 seizures a day and we tried a whole range of medications, none of which worked, and some of which affected her breathing and heart rate.

‘‘Around two years ago we started using cannabis oil and her seizures – and the severity of them – have decreased markedly. Now she’s down to one a day, and on some days none.

‘‘I’ve been raided twice by police, been to court once and received a 12-month bond and am back in court next week, but I have no other choice.

‘‘Without this, I think she’d be dead.’’

While he used to cultivate his own cannabis and make his own tincture oil, since the raids he said he had now been forced to procure it on the black market.

The type of oil the father gives his daughter is low in THC (tetrahydrocannabinol) – the chemical responsible for most of marijuana’s psychological effects – so it calms her without giving her a ‘‘high’’.

Another speaker at the symposium, Dr Andrew Katelaris, was deregistered in 2005 after refusing to stop recommending and supplying cannabis to patients – including children with epilepsy.

Despite being arrested several times and charged with a range of drug offences, Dr Katelaris still produces cannabis oil for patients from a clinic in Newcastle.

He said the oil was sourced from plants grown specifically for their concentration of cannabidiol (CBD), a non-intoxicating cannabis compound with therapeutic properties.

‘‘Prohibition has created a more dangerous and unbalanced form of cannabis, with plants bred high in THC for maximum psychotropic effect,’’ Dr Katelaris said.

Opponents of medicinal cannabis have concerns that users could become addicted, while studies have linked chronic marijuana use and mental illness.

- Lisa Wachsmuth