He said the child disability allowance was far less clear because it did not cater for the extra care and attention families must take when caring for a child with coeliac disease.
"When your child has just been diagnosed it can be very stressful and the last thing you want it a confusing system. You have to take some big steps at home, you might have to take time off work to check out the kindy or parties where your child might be exposed [to gluten]. If the child gets sick you have to take more time off work."
Mr Sunderland said the organisation had been in discussion with the Ministry of Social Development (MSD) and Work and Income for many years to try and clarify and standardise the process.
"We need something in writing that we can use and their staff can use to make sure we are on the same page," said Mr Sunderland.
He said the inconsistency stems from a lack of education around coeliac disease.
"It is often confused with an allergy; it's a life-long autoimmune disorder."
He said the response from Winz had been positive, but thought the issue might be at the bottom of their list.
"The people from Winz are waiting to sort this out - there's no brick wall there," he said.
Allergy New Zealand CEO Mark Dixon said the process of applying for the child disability allowance was ad hoc, and seemed to change on who you are and who you talk to.
"At Winz they aren't very clued up with it. Primary care and GPs aren't very across it either. There's no clarity in the criteria."
He said a lot of families get denied and cannot explain why.
"It going to cause some controversy but it appears that it has to do with the budgets in each office. It's very subjective."
He said whether someone received the allowances largely depended on GPs and primary care providers knowing about the allowances, but a lot do not.
MSD declined an interview, but a spokesman said any suggestion of a site or local office budget or Work and Income assistance being limited by a budget was misguided and totally inaccurate.
"Assistance is granted based on need and the meeting of clear eligibility criteria."
In a statement the spokesman said that regional health advisers and health and disability coordinators regularly discuss disability allowance with doctors during phone conversations and during personal visits to practices.
"Disability allowance is also promoted to the broader health and disability community; this includes having the regional health and disability team and/or Work and Income stands at health and disability forums and expos, talking to hospital staff, e.g. social workers and paediatricians, where hard copy brochures are made available," he said.
As at the end of December 2014, Winz paid out 7702 disability allowances linked to special food cost claims and totalled almost $200,000 weekly.
The maximum special food allowance is $61.69.
Student gets help for food bill
Student Kyra Dawson, 25, suffers from coeliac disease and receives $32.65 to help with her additional special food costs.
She became aware of the allowance by chance when she was applying for her student allowance.
"I was just applying for my student loan in first year, and then applying for my allowance. It said 'do you have a disease' and I clicked yes, because it's called coeliac disease. Then it said, you can apply for a disability allowance."
Ms Dawson said she had had coeliac disease since she was 12, but it took seven years to work out what was happening.
She said learning to deal with the disease was a process of trial and error.
"I had a Milo every morning, and then one day my mum messages me and says 'I found out Milo is made from malt and barley' and both of those have gluten in them.
"I think for people who find out later it's kind of hard because you're so used to being able to eat whatever you want," she said.
Ms Dawson remembers a neighbour whose child was diagnosed at age seven.
"The kid was always really skinny with a bloated tummy, it took ages for them to work it out."
She said applying for the allowance was relatively straight forward, once she found out about it.
"I had to get six weeks' worth of receipts to prove I was buying gluten-free food, then I had to go to a doctor to get her to fill out a form about my disease and what I was going through. She was a student health doctor, and she didn't even know about it when I went to her."
Ms Dawson has met other coeliac sufferers and most were surprised to learn they might be eligible for the allowance.
"It's just really helpful because breads and pasta and even eating out is always more expensive. It's just that little bit extra and because I'm a student I find it really helpful."
