"One of the things we're hoping Chase will be able to do is move things out of the way for Hannah, open doors, fetch stuff, retrieve items, give her more independence.
"If she drops something on the floor she can't pick it up again. Doors, unless she can bash it open with her chair, she can't get through."
Assistance Dogs New Zealand instructor Julie Hancox said Chase will also work as an icebreaker for Hannah, so she is able to socialise with other people.
"People are interested in the dog, then you get people asking what is the dog's name. Often people feel awkward around wheelchairs and the like so it gives them something to occupy themselves; patting the dog while they are talking."
Chase will be able to go wherever Hannah goes, including Starship Hospital. Hannah has already had surgery on her spine - a major procedure where two titanium rods were inserted either side of her spine as she was hunched over, putting pressure on an already small lung.
The surgery is not common and New Zealand is one of the only countries to perform it; Hannah is one of around 20 children to have had the surgery. With weak lungs, Hannah is prone to respiratory illness and has undergone a femur and pelvic reconstruction.
Mother Donna cares for Hannah full-time. "When she becomes unwell, it is care 24/7. That is when we go into hospital. Waikato don't have a paediatric ICU, so we have to bypass that and go to Starship.
"You often get support through organisations and charities, but we don't have a foundation for Hannah because we don't have a diagnosis."
Hannah attends the conductive education unit at Woodstock School and when she is well enough, she attends a mainstream classroom.
"It is really hard because you can't completely isolate Hannah because Mark goes to work, Sean goes to school. Sometimes when there are a lot of bugs going around, I will just keep her in the unit rather than take her into the classroom. She is very aware when someone is coughing - you go to the other side of the room!"
Due to Hannah's fragile bones, she needed a gentle dog who would not jump up or get rough. Ms Hancox said each dog is fitted to the family and will undergo additional training once placed if its's needed.
Julie said until the organisation has significant funding behind them, the cost of training has to be passed onto the families.
"We ask clients to help us by raising money for Assistance Dogs New Zealand - they set a target of $20,000. .
"It is huge, but until we get [big] funding behind us, there isn't much we can do. Unfortunately it means some clients just don't go ahead, because they don't have the time or the energy to fundraise. Hopefully we can get established enough so we can reduce the cost."
The Mullins will hold a garage sale at Mr Mullins' workplace, Telsa. Debbie Ross from Telsa said the company usually does some sort of fundraising and "thought this time we'd do something that was a bit closer to home".
The garage sale will be held in the basement garage of 18 Von Tempsky St on October 18 from 8am. The Mullins are seeking donations of items and larger items will be listed on Trademe under the search, Assistance Dogs New Zealand. Items can be dropped off between 9am and 5pm Monday-Friday at Tesla Consultants, 18 Von Tempsky St. Contact Debbie or Karen on 834 6460.
To donate directly to Hannah, visit www.assistancedogstrust.org.nz/index.php/donate-now and use 'Hannah' as a reference.