Dr Antony Kidman died on Friday after suffering a suspected heart attack in the restaurant of an exclusive hotel in Singapore, where he had travelled to spend time with his youngest daughter Antonia and his six grandchildren.

As Nicole flew to Australia to be with her family, Antonia Kidman's husband Craig Marran endured the difficult task of visiting a Singapore mortuary to formally identify his father-in-law.

Marran visited the mortuary at Singapore General Hospital on Saturday morning and spoke with local police and undertakers from Singapore Casket.

He declined to speak to the media, the Straits Times newspaper reported.

Dr Kidman, 75, was director of the Royal North Shore Hospital's Health Psychology Unit and director of the  Health Psychology Unit at the University of Technology, Sydney.

Tributes poured in for a "greatly admired man" who made a "significant impact" across his field.

Professor Helen Christensen, director of the Black Dog Institute, said: "Dr Antony Kidman made an enormous contribution to mental health research and clinical care in Australia. His skill and passion for empowering the patient laid the foundations for a new generation of self-driven psychological care."

Judy Proudfoot, an Associate Professor at the University of New South Wales and director of e-health at the Black Dog Institute said: "In addition to his clinical work, one of Tony's great strengths was his ability to take psychological theory and research and convert it into very clear practical self-help advice and strategy. His series of self-help books changed the lives of thousands of people around the world."

Fairfax Media can confirm that after landing in Singapore on Thursday night, Dr Kidman awoke at the prestigious Tanglin Club the following morning where he enjoyed a routine work-out and then sat down  to breakfast. However, before Dr Kidman had even had the chance to rendezvous with his daughter, tragedy struck when he collapsed in the restaurant. It is understood that guests attempted to resuscitate him but he was later pronounced dead  at hospital.

On Saturday morning, Antonia returned from Singapore to the family's home on Sydney's lower north shore. Nicole, meanwhile, was still in transit, having learnt of her father's death while she was home alone in Nashville. Her husband Keith Urban posted a message to fans on Facebook on Saturday morning in which he spoke of his family's pain.

"I'm so very sorry that I cannot perform this weekend," he said in reference to his scheduled performance at the Washington State Fair. "We are in a deep state of grief at the passing of Nic's Father and are heading to Australia to be with family. We want to thank everyone from the bottom of our hearts for their love, prayers and support through this devastating loss."

Nicole's father regularly accompanied her to functions, his most recent appearance being in June, on his daughter's arm, with Urban, at the  Swisse Celebrate Life Ball in Melbourne.

When asked at the event what was great in her life, Nicole replied: "My family. My dad's here... here's my dad," she said proudly, adding: "I've got my men here tonight."

UTS vice-chancellor Professor Attila Brungs also paid tribute to Dr Kidman:

"It is with great sadness that we learn of Dr Tony Kidman's sudden passing," she said. "During his 43 years at the University of Technology, Sydney, Tony has contributed greatly - as a colleague, as a researcher, and as a health practitioner. Our thoughts are with his family at this time."