Dr Antony Kidman, 75, died on Friday after suffering a suspected heart attack. He 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.

Dr Kidman had arrived in Singapore on Friday night to spend time with his other daughter Antonia and his six grandchildren. However, he collapsed during breakfast on Friday in the exclusive Tanglin Club before he was able to see his family.

It is understood that resuscitation attempts were made, but Dr Kidman was later pronounced dead at hospital.

Nicole arrived in Sydney on Sunday morning after hearing of her father's death while home alone in Nashville, Tennessee.

Her husband, singer Keith Urban, was due to perform at the Washington State Fair on the weekend, but pulled out with a Facebook message to fans on Saturday morning.

"I'm so very sorry that I cannot perform this weekend," he said. "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 sister Antonia returned to the Kidman family home on Sydney's lower north shore on Saturday while her husband, Craig Marran, remained in Singapore to formally identify the body of his father-in-law at a hospital mortuary.

Tributes have poured in for Dr Kidman, lauded as a "greatly admired man" who made a "significant impact" in 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."