Dr Khan died on Monday, aged 86, after a long battle with cancer.

A private funeral was held on Thursday, at which friends and family remembered a kind-hearted man with a wicked sense of humour who dedicated more than half a century to caring for his patients.

Dr Khan was born in Sydney in 1926, the first of fraternal twins and one of 10 children.

He joined the Australian navy in his late teens at the end of World War II and was immediately shipped to Japan as part of an international contingent tasked with overseeing post-atomic bomb "clean up" duties.

Those who knew him well say vivid memories of seeing horse carcasses in the street and the outline of where people had fallen to their deaths stayed with him for life.

On returning home, he enrolled in medicine at Sydney University, gaining his first medical deployment at St Vincent's Hospital.

In 1954, Dr Khan moved his family to Wollongong to work with his brother Teddy, also a general practice doctor, at Fairy Meadow.

Shortly after arriving he set up a small practice in the front room of a house on Gipps Road at Gwynneville and lived in the rear rooms with his wife and children.

Dr Khan later moved the practice a few doors down to 220 Gipps Road, where he continued to work until his retirement in 2005 at the age of 80.

His daughter, Jenny Smiley, also a GP, now runs the practice.

Dr Smiley said she had many fond memories of working with her father.

"He had a wonderful sense of humour and was a great teacher," she said.

"If he had an interesting or difficult case he would often call me in from the next room and quiz me on how I would treat it.

"He especially loved having children come into the surgery - he could make you laugh even if you were feeling sick."

Dr Khan was the founding director of the Wollongong After Hours medical service and for many years worked as an honorary paediatrician at Wollongong Hospital until patient numbers were large enough to attract a full-time specialist.

It was during these years former Wollongong Hospital medical superintendent, Ian Dixon, got to know Dr Khan best.

Speaking about his late friend this week, Mr Dixon said Dr Khan hailed from a time when GPs were more than simply doctors.

"He was father-confessor, a surgeon, a midwife; he was practically mayor of Gwynneville," he said.

"Keith was an old-fashioned GP in the way that he was never off duty - he dedicated his whole life to caring for his patients, day and night.

"He maintained that level of commitment right up until he got sick and retired."

Dr Khan is survived by his wife, Voda, three children, Jenny, and twins Trevor and Alison, and seven grandchildren.