A NSW father could be jailed for giving his four-year-old daughter "life-saving medication".

Michael Lambert’s four-year-old daughter Katelyn suffers from one of the most vicious forms of childhood epilepsy.

As an infant she would sometimes have more than 1,000 brain-damaging seizures a day — that’s one every 15 seconds.

When Katelyn reached six months of age, and it was clear regular treatments had failed her, Lambert turned to medical cannabis, which he said “saved her life.”

Before he began treating her with cannabis oil, she had a one in two chance of dying before she was 18 years old and a 100 per cent chance of intellectual disability.

“Katelyn is well. Every day without a seizure is a good day,” he told Mamamia.

Lambert has a Federal permit to import cannabis but under NSW law it is still illegal for him to possess it, he said.

Regardless, there is a law that allows NSW police to use their discretion when it comes to the drug.

Lambert's home-grown cannabis plant. Source: supplied

Rather than turning a blind eye, they have chosen to charge Lambert with a slew of offences under the under the Drug Misuse and Trafficking Act for growing the plant in his backyard.

"Call them what you like — tattooed healers with tasers; underqualified neurologists with guns," he said, referring to the NSW police force.

"Whatever you call them, you can't call them qualified to come to the house of a catastrophic epileptic and demand her medicine, which her neurologist wants her to continue to take.  "

Lambert plans to fight the charges in court and has already spent more than $30,000 on legal fees and medical reports — all because he wanted to ease his child's suffering.

"We will win, because under common law it is not a crime for a father to break a stupid law in order to save his daughter's life.

"You can tell the Premier we are still breaking the law in NSW because we love our Katelyn and she loves cannabis."

Medical cannabis advocate Lucy Haslam understands Lambert's situation better than most.

Her son Dan suffered from terminal cancer and the former nurse claims medicinal cannabis was the only way to relieve his nausea and pain.

Lucy Haslam explains her plan for an amnesty for patients using medicinal marijuana to the ABC's Fran Kelly. (Post continues after video.)

After his death, Haslam founded United in Compassion and has consistently lobbied the NSW state government for a more compassionate approach.

Hence, she started a petition on change.org, using Lambert's story to illustrate the need to legalise medical cannabis.

Haslam is advocating to replace the existing Terminal Illness Cannabis Scheme with what she has labelled the Compassionate Access Cannabis Scheme.

"I believe that compassionate access to medicinal cannabis is important, because despite the war on drugs and the long history of propaganda around cannabis, many very sick patients find that it is a great source of relief for many severe and debilitating symptoms," she told Mamamia.

"Unbiased research is supporting the therapeutic benefits of cannabis and slowly attitudes are changing, but patients that are needing medicinal cannabis urgently, cannot afford to wait for the slow clinical trial validation process and are forced to become criminals just to manage their symptoms.

"It is a human rights issue that requires compassion and common sense."

Her petition has already garnered more than 3,000 signatures.

Feature image: change.org