Abby Hartley's ordeal started with a twisted bowel. Now, her family is facing a huge medical bill.

A Kiwi mum who has spent more than three weeks in a coma needs $160,000 to be flown back to New Zealand from Bali.

Doctors treating the Hamilton mum-of-two say she has the best chance of waking up back home.

Abby Hartley, 41, was rushed to a Bali hospital with a twisted bowel on August 1.

It had been the first day of her "second honeymoon".

READ MORE: Hamilton woman seriously ill in Bali as insurance declines cover

Emergency surgery was performed to remove a section of her bowel, but two days later she suffered acute respiratory distress syndrome and was put into an induced coma.

She has since suffered kidney failure, a collapsed lung and several infections.

Oxygen deprivation means she's also suffered brain damage, but no one will know the extent of the damage until she wakes up, her 20-year-old daughter Sophie Hartley said.

HARTLEY FAMILY The Hartley family in hospital in Bali. From left: Sophie, Abby, Richard and Toby.

Hartley's son Toby and husband Richard are still overseas, although their visas expire within the fortnight. Sophie is back in Hamilton trying to operate the family business.

The family were initially told Hartley could fly home commercially for about $60,000, with 9-10 seats needed for the accompanying stretcher, equipment, doctor and nurse.

But Hartley's condition has become too unstable and she will need to be flown via an emergency aircraft (EVAC) costing up to $160,000.

Insurance cover has been declined as Hartley's condition was deemed pre-existing.

The family plan to remortgage their house and have so far raised more than $110,000 through a Givealittle page.

SUPPLIED The Hartley family from Hamilton, from left: Richard, Abby, Sophie and Toby. Abby has been in a coma in Bali for more than three weeks.

Hartley will have the best chance of waking up back home and surrounded by loved ones, Sophie said.

"[The doctor] said we've run of options so you guys just need to get her home. I know for a fact that if she's home there will not be a single minute that she's alone. There will always be someone there.

"You just sit there, hold her hand, stroke her hair. I was plaiting her hair and playing her voice recordings from her friends and family."

Hartley is the kind of person who stops to chat with strangers in supermarkets or the Warehouse, Sophie said.

"I didn't go a day without talking to her. Now it's been three weeks and I haven't spoken to her.

"I've had so many people message me and say. 'I served your mum a coffee at a cafe and she was such a nice person'."

The holiday was meant to be a second honeymoon, a chance for the couple to renew their vows. She had been so excited, Sophie said.

More than three weeks later, Richard has been at Hartley's bedside everyday, holding her hands and talking to her. "She flutters her eyes sometimes and Dad will kind of go 'Abby' and she'll open her eyes and close them again.

"Some days she'll have her eyes open all day. But we don't know whether that's her responding."

Doctors stopped sedating Hartley on August 15, but she remains in a coma and has become immune to the antibiotics needed to treat infections, Sophie said.

"We're just waiting for a miracle now. We've been through enough, surely there's something around the corner.

"I just really want mum home. If we could get her out tomorrow we would get her out tomorrow."