It’s the announcement retired nurse Lucy Haslam and her family has been waiting to hear.

The New South Wales' government has announced plans to establish a clinical trial of medical cannabis for patients suffering from a range of debilitating or terminal illnesses.

Premier Mike Baird announced the clinical trial in parliament and said police will be able to continue to use their discretion to not charge terminally ill adults using cannabis - which will be formalised in new guidelines.

Lucy, who has waged a public campaign to legalise medical cannabis, labelled the announcement “exciting”.

“It’s a very good outcome to have the government come on board and finally they are going to start treating this a bit seriously, getting behind it - it’s just been such a long time coming,” she said.

“Mike Baird is such an amazingly unaffected politician, he’s a really decent human-being and now that he wants to drive it, I think it’s in good hands.

“I think they are going to take their time and get it right but not too much time, they’ve given themselves until the end of the year as the deadline to have things sorted out, so that’s pretty good.

“We have had lots of obstacles thrown up in our way and finally I feel like they’ve all settled down and I think Mike Baird is truly going to make this happen.”

Lucy and her husband, a former drug squad police officer, have been fighting to decriminalise the medical use of cannabis after their son Daniel, 24, began using cannabis to overcome nausea, vomiting and poor appetite as a result of the chemotherapy used to treat his terminal bowel cancer.

The Tamworth family launched an online campaign to decriminalise medical cannabis, which has received more than 196,000 signatures of support.

The Victorian government is also removing legislative barriers to clinical trials of medial cannabis, while Western Australia has called for a national approach to trials.

Lucy said it’s vital to have a national approach to legalising medical cannabis.

“We have got to drive this nationally now, it’s silly to have people being disadvantaged by where they live,” she said.

“I just want to make sure that they get this right - they’re still talking about quantities that aren’t really going to cater for people who are treating cancer with cannabis.

“They have got to get that right and then ultimately to drive it around the country.”

The NSW Nurses and Midwives’ Association (NSWNMA) Council has supported the Haslam family’s fight.

Medical cannabis is legal and regulated in the United States, Canada and several European countries where it’s used to alleviate symptoms for Parkinson’s Disease, Multiple Sclerosis, Crohn’s Disease, and other chronic pain and post traumatic stress disorders.