When applying for a KiwiSaver withdrawal to fund weight loss surgery in New Zealand, the GP medical letter is the most ...
When applying for a KiwiSaver withdrawal to fund weight loss surgery in New Zealand, the GP medical letter is the most important document.
If you haven’t read it yet, our main pillar breaks down the entire process from eligibility to approval:
👉 KiwiSaver for Weight Loss Surgery (2025 Guide)
KiwiSaver providers rely heavily on your GP’s statement because it explains why your condition requires surgery and why delaying treatment is not medically safe.
This guide includes:
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What KiwiSaver providers want from a GP letter
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A detailed checklist
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A complete template you can give your GP
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A finished sample letter
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Mistakes to avoid
1. Why the GP Letter Matters
KiwiSaver providers must determine whether weight loss surgery is:
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medically necessary
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essential for long-term health
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supported by a qualified practitioner
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not safely postponed
Because they cannot personally evaluate every patient, they use your GP’s letter as the core medical justification for the withdrawal.
A weak or vague letter is the #1 reason KiwiSaver applications are delayed or declined.
For a broader explanation of how KiwiSaver medical withdrawal works, read the full guide:
👉 Complete KiwiSaver Withdrawal Guide for Bariatric Surgery
2. What KiwiSaver Providers Expect to See
Every provider is slightly different, but most (Milford, Booster, Simplicity, AMP, Fisher Funds, ANZ) expect the letter to include:
✔ Diagnosis
Your primary medical condition(s).
✔ BMI and key health indicators
Height, weight, BMI, and recent clinical trends.
✔ Related health conditions
Diabetes, hypertension, sleep apnea, mobility issues, etc.
✔ History of non-surgical treatment attempts
Diet plans, medications, supervised programmes, behavioural treatment.
✔ Why surgery is medically necessary
The medical rationale for recommending bariatric surgery.
✔ Expected improvements
Health, mobility, metabolic improvements, and long-term prognosis.
✔ Why the surgery should not be delayed
Providers must evaluate urgency.
Including these points greatly increases the likelihood of approval.
3. GP Letter Checklist
Give this checklist to your GP to ensure the letter meets provider expectations:
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Patient full name & DOB
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GP practice details
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Diagnosis
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BMI + height + weight
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Comorbidities
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Treatment history
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Statement of medical necessity
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Expected benefits of surgery
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Risks of delaying treatment
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GP signature & contact info
4. Copy-Paste GP Letter Template (2025)
Below is a complete, professional GP letter template that can be used as-is or customised.
GP Medical Letter Template
[GP Practice Name]
[Address]
[Phone]
[Email]
[Date]
To whom it may concern,
I am writing in support of [Patient Full Name, DOB], a patient under my care who presents with weight-related health concerns requiring medical attention.
Medical Background:
The patient currently has a BMI of [BMI Value], with a height of [X cm] and weight of [X kg]. They also present with:
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[Condition 1]
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[Condition 2]
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[Condition 3]
These conditions significantly impact their daily functioning, overall health, and long-term prognosis.
Previous Treatments:
Non-surgical treatments such as [list attempts] have been attempted without sustained success.
Medical Necessity of Surgery:
Bariatric surgery is, in my clinical opinion, medically necessary to prevent further deterioration in this patient’s health. Without surgical intervention, their condition is likely to worsen, increasing the risk of serious long-term complications.
Expected Benefits:
Surgery is expected to improve:
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metabolic health
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cardiovascular risk
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mobility
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quality of life
Conclusion:
I strongly support this patient’s application for a KiwiSaver early withdrawal to fund this medically necessary treatment. Please contact me if further information is required.
Sincerely,
[GP Name]
[Qualifications]
[Practice Name]
5. Example Completed Letter
This sample helps illustrate what a strong, complete letter looks like.
Example GP Letter
To whom it may concern,
I am the GP of Sarah Williams (DOB 12/08/1987). Sarah has a BMI of 42.3 and presents with hypertension, insulin resistance, and moderate sleep apnea.
Over the past five years, she has attempted multiple supervised weight-loss strategies with limited success, including dietary plans, exercise programmes, and medication-supported weight management.
Based on her medical condition, bariatric surgery is clinically indicated and medically necessary. Without timely surgical intervention, her comorbidities are likely to worsen, and her long-term health will be significantly compromised.
I strongly support her application for a KiwiSaver withdrawal to fund this essential treatment.
Sincerely,
Dr. Matthew Clarke
MBChB, FRNZCGP
Healthy Life Medical Centre
6. Common Mistakes GP Letters Should Avoid
❌ No BMI listed
❌ No mention of comorbidities
❌ Generic wording with no clinical details
❌ Short, 2–3 sentence letters
❌ No treatment history
❌ No mention of urgency
❌ Patient-written letters submitted as GP letters (providers reject these)
A strong letter demonstrates medical reasoning, not motivation or general statements.
7. Tips for Getting a Strong Letter
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Share this guide with your GP before your appointment
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Bring your medical history
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Ask your GP to be specific
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Ensure all comorbidities are listed
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Confirm they address why surgery cannot be delayed
For a complete overview of the KiwiSaver process, including eligibility rules, timelines, and documents, see the main guide:
👉 KiwiSaver for Weight Loss Surgery (2025 Guide)
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