Those who have had breast, heart and amputation procedures suffered some of the worse pain, they said.

Experts in pain management said 20 per cent of the 2.3 million Australians having surgery each year experienced persistent pain at the site of their operation one year after surgery, and that about 5 per cent had severe on-going pain.

A meeting of pain management specialists heard that nerve damage and genetic predisposition to pain were key reasons.

Pain management specialist Audun Stubhaug, of Oslo University, told the Australian and New Zealand College of Anaesthetists’ conference in Singapore yesterday that people more sensitive to painful stimuli before surgery had a higher chance of post-operative pain.

And there was evidence people with a high or low body mass index, smokers and those who have had chronic pain, depression and anxiety, were at greater risk.

Professor Stubhaug said tests could predict about 80 per cent of those who would experience chronic pain after surgery.

Better screening could help doctors with their anaesthetic technique and pain management after surgery, he said.

Professor Stubhaug said sometimes less invasive alternatives could work as well — if not better — than surgery.

Pain specialist Mick Vagg, of Geelong, said many with osteoarthritis whose knees were replaced were not aware 20 per cent would still have pain and 5 per cent would be less mobile than before the surgery.

“Some people are worse off,” Dr Vagg said.