Tamahanga Tukunga is undergoing dialysis three times a week at Auckland hospital for end stage kidney disease.

A young man with kidney failure is pleading to stay in New Zealand, knowing he'll face a painful death if deported to Tonga.

Tamahanga Tukunga is among a growing number of Tongans requesting help because dialysis is not available in their home country.

"I don't want to die," the 24-year-old said. "I'm still getting used to life."

LAWRENCE SMITH/STUFF Tamahanga Tukunga says his experience has been overwhelming and initially made him depressed.

Dr Gerhard Sundhorn, a public health researcher at the University of Auckland, said Tukunga's health would decline rapidly if he was deported to Tonga.

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"It's basically a death sentence," Sundhorn said. "He'd die within a matter of weeks, and it would be quite a horrific death."

JARRED WILLIAMSON/STUFF Tukunga was admitted to Middlemore Hospital on 6 March 2017 with end-stage kidney failure.

Tukunga arrived in Auckland in March last year on a one-month visitor visa.

He declared on his visa application he did not have any medical condition that required or could require renal dialysis or hospital care during his stay in New Zealand.

The law student was admitted to Middlemore Hospital two days later with end-stage kidney failure. He was previously fit and healthy, without diabetes, and doctors don't know why his kidneys failed.

GIVEALITTLE Tukunga's relatives are paying Counties Manukau DHB $500 a week to help cover treatment costs.

Since then Tukunga has received dialysis three days a week; as a foreign national he's not entitled to that treatment and could be deported to Tonga within a year.

That's despite his relatives doing everything they can to cover costs, including sausage sizzles back in Tonga, and sending yams to sell in New Zealand.

They are making voluntary payments of $500 a week to Counties Manukau DHB, although that only goes part of the way to covering the cost of dialysis, which can run to $80,000 a year.

LAWRENCE SMITH/STUFF Tamahanga Tukunga would die within a few weeks if he's deported to his home country of Tonga.

Andrew Simpson, chief medical officer at the Ministry of Health, said hospitals were obliged to provide treatment to "anyone requiring acute services".

"If they are not eligible for treatment, they can expect to be invoiced for the services they received," he said.

However, DHBs are often forced to write off the costs as bad debt, with Auckland DHB alone pursuing $13.6 million in unpaid costs from foreign patients as at August 31, 2017.

JUSTGIVING Rugby player Sione Vaiomounga and his wife were stranded in Romania after his kidney failure diagnosis.

Tukunga said his experience had been overwhelming and initially made him depressed.

"I'm at an age where I see my fellow students graduating and moving on with their lives, and I'm here at a halt, a stop, where I can't continue on," he said.

His case was one of several considered recently by the Immigration and Protection Tribunal on humanitarian grounds.

GETTY IMAGES Sione Vaiomounga makes a break for Tonga against Scotland at the IRB Sevens in Hong Kong in 2011.

In its ruling, the tribunal found "exceptional" circumstances and said it would be "unjust and unduly harsh" to kick Tukunga out of New Zealand.

It granted him a one-year work visa so he could explore further treatment options.

One of the factors considered by the tribunal was a lack of treatment in Tonga.

KENT BLECHYNDEN/STUFF Dialysis machines are used to purify someone's blood if their kidneys can't perform their normal function.

Sixty people die in the Pacific nation each year from chronic kidney disease, and the Tongan government is yet to follow through on a 2012 promise to establish a dialysis unit.

The tribunal said the New Zealand government needed to consider how to respond to Pacific citizens requesting treatment.

"The high and growing number of Tongans needing dialysis and its continued unavailability in Tonga makes it unsurprising that some Tongans will look to New Zealand, where many have family members, in the hope of being able to stay alive," it said.

New Zealand isn't the only country providing treatment for desperate Tongans; rugby player Sione Vaiomounga became stranded in Romania three years ago after being diagnosed with kidney failure while playing for a local team.

Vaiomounga also faced death if deported to his home country.

Sundhorn said deciding whether to provide compassionate treatment for foreign nationals was a difficult ethical dilemma.

"We've already got a huge problem here," he said. "Providing dialysis for type-two diabetics and kidney transplants will cripple our health system."

Sundhorn suggested the government should consider directing Pacific aid to projects such as a dialysis unit for Tonga.

"We are the big brother to a lot of these Pacific nations, and it's a good idea for New Zealand to take a stronger role," he said.

For Tukunga, it's a case of surviving from one day to the next.

"Of course I'm homesick, I miss my parents," he said.

"But it doesn't really matter where I am, just as long as I'm alive."