He is New Zealand's first formally trained paediatric surgeon and after 40 years of service Dr Stuart Brown is putting down his scalpel and retiring.

Known for his dedication, the Waikato Hospital paediatric surgeon has performed thousands of surgeries and is fondly described by his colleagues as simply 'irreplaceable”.

New Zealand's first formally trained paediatric surgeon Dr Stu Brown finishing up his last surgery at Waikato Hospital in December 2015. Photo: Waikato DHB

After performing his last surgery in December, Dr Brown says he felt privileged to have worked with so many talented people.

'There has been enormous changes in the hospital over the years. And I have seen [Waikato Hospital] grow over the years into the place it is now. I'm very ambivalent about giving up, it is so much a part of my life,” he says.

'However, it came home to me a few weeks ago when I went to renew my passport. The man said ‘why don't you wait a couple of years and you can get a 10 year long one', when I told my partner she said well that should see me out.”

For the past four decades Dr Brown has been viewed as the pillar of paediatric surgery at Waikato Hospital and the news of his departure has been particularly hard on staff.

Fellow paediatric surgeon Dr Askar Kukkady describes his colleague as a man who is always 'low key” that doesn't draw attention to himself.

'He is the ultimate for us, a brilliant surgeon,” says Dr Kukkady. 'He is always here for us, on many occasions he has cancelled private lists just to be here for the public and staff.”

One notable surgery Dr Brown performed, alongside Dr Kukkady, was to separate conjoined twins Abbey and Sarah Hose back in 2004.

At the time, the gruelling 22-hour-procedure was hailed as an international success. Dr Kukkady was the head surgeon on that case and says it is his best memory of ‘Stu'.

'When we separated the conjoin twins, having him next to me was the most reassuring thing – he let me do it but he offered me the confidence,” he recalls.

'That is really it, we always feel more confident when he is standing next to us.”

While charge nurse Heather Glenn adds that Dr Brown's gentility and humility is not just revered among his colleagues but also his patients.

'They just love him, he is down to earth and is able to find a way to connect with anyone at any level whether that be a patient, their family, a nurse a house surgeon – whomever,” says Heather.