Calls for PHARMAC to fund what's being called a desperately needed bowel disease medication

Patients are marching through Wellington streets this afternoon to support a petition for the funding of ustekinumab .

The petition's garnered more than 30-thousand signatures, and will make its way to PHARMAC headquarters, before being presented to Act leader David Seymour at Parliament.

Ustekinumab is funded in more than 35 countries overseas, and is used to treat chronic bowel diseases such as Crohn's disease and ulcerative colitis.

Crohn's and Colitis NZ chair Richard Stein says without the treatment, doctors have to condemn patients to a life of unnecessary pain and debilitating surgery.

He says New Zealand has one of the highest rates of chronic bowel diseases in the world, with over 20 thousand people affected.