Alex Renton, 19, died in July 2015 after a battle that involved the groundbreaking use of medicinal cannabis.

Friends and family have praised the fighting spirit of the Nelson teenager, who died on Wednesday, as Associate Health Minister Peter Dunne says prescribing medical cannabis was worthwhile.

Alex, 19, who died on Wednesday, had been in hospital since April 8 in "status epilepticus", a kind of prolonged seizure. It was not known what caused the seizures.

Associate Health Minister Peter Dunne, who last month approved a petition to the Government from Alex's family to allow him to be treated with a medicinal cannabidiol oil, Elixinol, told TVNZ the effort of prescribing the drug had been worth it.

"I'm sad that the outcome hasn't been favourable for Alex."

Dunne told TVNZ Alex's case had touched "the nation's heartstrings".

His family posted on a Facebook page on Wednesday night that he had died.

"This evening our beautiful warrior Alex passed peacefully away.

"He was surrounded by his family, listening to his own music with a tummy of mum's food.

"We thank you all from our hearts as you kept us strong during this journey. His spirit is amongst us all as he taught us so very much. We love you dear Alex (aka Ratty) xxxxxxx ."

Alex had been given his first dose of the oil on June 16 after it arrived from America. His sedation medication treatment was reduced and he regained consciousness and his seizures stopped in that first week.

On Monday this week, his mother Rose posted on Facebook: "Alex is holding his own maintaining his own breathing! He shows courage, strength and fortitude as he battles towards better health. Keep prayers flowing. We are now feeding Alex our own meals with support from Hospital. This continues to be the most challenging event of our lives as a family, support around NZ is incredible, thank you xx. Rose"

On Wednesday Alex's sister, Jessie Renton, posted on her Facebook page: "Fly high my darling boy, I know you will be next to me every step of the way. I love you Alex and couldn't be prouder of everything you have achieved. You are free now my bro."

Many others who followed his journey also left messages on a Facebook page dedicated to the teenager.

Aroha Montgomery posted: "I am really sorry to hear of your loss, what a fighter. I was Alex's Nelson Bays Physio for the past two years and he was one of the most polite, friendly and amazing teenagers I encountered in Nelson and in my life. You raised an amazing son! To be able to leave this world surrounded by so much love is an incredible gift to give him. Thinking and praying for you all."

Labour MP Damien O'Connor, a former associate health minister, is working on a member's bill calling for better access to CBD (cannabinoid) for families who have already tried conventional treatments.

He had passed on his condolences to the Renton family, he said.

Alex's journey would only serve to keep the fight for better access to CBD for those who have tried other alternatives going, he said.

"As a tribute to the battle Alex was fighting, we will continue to work on the Member's Bill."