Dr Jeremy Ng, Singapore General Hospital's (SGH) head of general surgery, died on Saturday aged 48.

Colleagues, friends and former patients have offered heartfelt tributes.

Dr Ng was said to have died of cardiac arrest. It is understood that he collapsed after he went jogging at East Coast Park on Saturday. He leaves behind his wife and a son.

SGH said in a Facebook post on Monday that Dr Ng had made significant contributions to the delivery of clinical services, such as playing a key role in the development of acute care surgery. His work "has significantly reduced morbidity, mortality and length of stay of patients who require acute surgical care," it said.

The hospital said Dr Ng pioneered trans-oral thyroid surgery in Singapore - a scar-free procedure which is a safer alternative to conventional thyroid surgery.

SGH said Dr Ng was passionate about his work as a surgeon and was a strong advocate for his patients. "Jeremy leaves his mark as an exemplary clinician, outstanding surgeon and unassuming leader," said the hospital, adding that he would always make time for people.

"He will be remembered for his sincerity, personal warmth, humility and genuine kindness."

Commenting on SGH's post, administrative executive Audrey Ng, 42, said she will miss Dr Ng's "gentle spirit and caring attitude" towards her 70-year-old mother, whom Dr Ng treated for parathyroid disease.

She told The Straits Times: "I have never come across another doctor like him, who listens to the elderly and whose main priority is truly his patients."

She added that on one visit, she overheard him telling one of the nurses he had started his day earlier so he could attend to more patients.

Ms Azlina Johari, a senior staff nurse at SGH, said that Dr Ng treated everyone around him with kindness and respect.

Ms Azlina, 32, worked with Dr Ng at the hospital's endoscopy department five years ago. She later became his patient when she was referred to Dr Ng for a supraclavicular lymph node in 2018.

"Even though he had a full list of patients, he scheduled me for surgery the next day and removed the lump, which turned out to be lymphoma,"she said.

Ms Azlina said Dr Ng saved her life.

"Cancer scares are very worrying, but the way he communicated with his patients really helped them see the bright side in everything," she said.

"He had the gift of making everyone he met feel better about themselves."