For Christchurch mother Shelley Pratt being told her unborn son had cystic fibrosis was "devastating".

Ben, now 3, was diagnosed after a routine check while he was still in the womb showed he had a bowel blockage.

Further tests confirmed Ben had cystic fibrosis, a chronic lung disorder and the most common life-threatening genetic disorder affecting New Zealand children.

There is no cure but finding out early meant treatment could begin straight away.

"It was devastating . . . but it was quite good because we actually knew it was coming," Pratt said.

Cystic fibrosis affects several organs, especially the lungs and pancreas, by clogging them with thick, sticky mucus. It can cause shortness of breath, a chronic cough and repeated chest infections. The median life expectancy for those with cystic fibrosis is 35.

Ben's twice-daily physiotherapy and regular medication have become part of the Pratt family's life.

"I wouldn't say it becomes easy but it becomes part of your daily routine," Pratt said. "It's totally normal for him; he doesn't know anything different."

Physio often involved fun activities like trampolining and, Ben's favourite, blowing bubbles.

"Basically, it's any physical activity. You try to make it fun."

Pratt said she was "absolutely" hopeful a cure would eventually be found.

 ORGAN DONATION

The Government is being called on to establish "clear and binding" legislation to support those who want to donate their organs when they die.

The national cystic fibrosis Bubbles Week began on Monday to raise awareness of the condition that affects more than 500 New Zealanders, including about 100 in Canterbury.

Most people suffering from the disorder die in their 30s from lung damage, many while waiting for a lung transplant.

Although organ donation was not a "permanent fix" for those suffering from cystic fibrosis, it "buys them a few years", Cystic Fibrosis New Zealand chief executive Kate Russell said.

"We have a few people in their 40s and 50s, and one gentleman in Canterbury in his 60s but he's a rare case," Russell said.

There were about 15 cystic fibrosis sufferers on the waiting list for a lung transplant, but most would die waiting, Russell said.

A sufferer's lung function had to be at 30 per cent or lower before they were considered for the transplant list. Those who made it on to the list usually had only 12 to 18 months' life expectancy.

Cystic Fibrosis NZ was calling for the Government to establish a register that would need to be supported by legislation that limited the power of family members to overturn a person's clearly stated wishes to donate organs.

- Bubbles Week runs until Sunday. Donations can be made at cfnz.org.nz.

- © Fairfax NZ News