More MPs – including Education Minister Anne Tolley – have admitted getting their stomachs stapled.
Mrs Tolley and Maori Party MP Rahui Katene both confirmed they had undergone the operation, which shrinks the stomach and dulls the appetite.
They joined Maori Party co-leader Tariana Turia and National Party MP Chester Borrows, who said earlier this week that gastric-bypass surgery had improved their lives and should be available to more New Zealanders.
Ms Katene, who lost 11 kilograms, believed greater subsidies for the surgery would stop Kiwis putting themselves at risk through cheap surgery overseas.
She researched the operation before having it five weeks ago.
She heard from six people who knew of Kiwis having the surgery in Asia because of the $28,000 price tag back home, she said.
"The follow-up care was not good. They don't keep patients in the hospital, they keep them in a hotel to recover and there isn't medical staff in the hotel ... It's a big worry."
Ms Katene said stemming this tide was a major reason to make the operation more affordable at home, as safety standards in New Zealand hospitals were much better than in many other countries.
The cost to the Government of subsidising the operation, versus the $100,000-plus burden a diabetes sufferer would put on the health system over 10 to 20 years, spoke for itself, she said.
But she stressed that the Government should be helping only those patients who were ill now and in need of the surgery.
Those who could still turn their lives around through healthy lifestyle choices should be helped in that way, she said.
She intends to rally support within Parliament to lobby the Government for change as quickly as possible.
"We don't even need a law change, all we need is for the Government to have the money in place at the next Budget."
A spokesman for Mrs Tolley confirmed she had undergone the operation but did not want to comment further because it was a private matter.
Other public figures to have had the surgery include the late prime minister David Lange, former unionist Ken Douglas and Donna Awatere Huata, who had the government-funded Pipi Foundation pay for her operation.
- The Dominion Post
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