Sufferers of Crohn's disease and colitis are pleading with Pharmac to fund a drug that's available in Australia and 37 other countries.
They're worried that the current medicine's becoming less effective over time.
To watch children enjoying themselves at Camp Purple you'd think nothing was up.
But they all suffer from Crohn's disease or colitis. It's for life, there's no cure and the symptoms are horrendous.
"Diarrhoea, lots of stomach cramps and pain, blood when you go to the toilet, going to the toilet up to 20-25 times a day," psychologist Hollie Asprey says.
Many are picking up the courage to do activities like these for the first time.
"A lot of them have been isolated, they've missed a lot of school, they've been in hospital. A lot of them just haven't had the opportunity to spend time with peers," gastroenterologist Professor Michael Schultz says.
And they can share their experiences.
"We're all going through the same thing so we can relate to each other and talk about it," one says.
"We feel like we've been friends for like over ten years. Straight when we met like I feel like I know you, like just like that we connected," another says.
The camp is proving invaluable for their mental health but 16-year-old Nicole Thornton is campaigning for their physical health too.
She says the drug for treating Crohn's currently funded by Pharmac is becoming less effective for some patients as they develop antibodies to it.
"For those who don't have a drug, for those who react to the different medications that we have we need to bring in another option," Thornton says.
A petition with 30,000 signatures has been presented to Parliament for Pharmac to pay for Ustekinumab - a drug approved here but not yet funded.
"It's particularly hard for people in the medical profession to know that there are medications out there that can help and they're just not available they're just not funded," Prof Schultz says.
Pharmac has released a statement pointing out Ustekinumab's manufacturer sponsors Crohn's and Colitis NZ for about $20,000 which in turn helps pay for Camp Purple.
Pharmac says it recognises the need for further treatment options but says it's reliant on budget availability and, in some cases, better commercial arrangements from the pharmaceutical companies.