A doctor who used a tube and his mouth to relieve an elderly airline passenger's inability to urinate on a flight to New York has denied staging a "moral show" to save the patient in response to online suspicions about his motivation.

"There would have been risks of failure, complications and infections. For a professional doctor, it would not have been cost-effective to make such a risky show," said Zhang Hong, a doctor with the First Affiliated Hospital of Jinan University in Guangzhou, Guangdong province.

Zhang, 55, sucked mouthfuls of urine from an elderly man who was unable to urinate because of a bladder rupture during an international flight from Guangzhou to New York early Tuesday morning.

"It was not worthy of such a risky 'trade'－even Warren Buffett would not do so," Zhang said in a text message on Sina Weibo on Friday.

After reports of his act were posted online, Zhang became the center of heated debate, with some saying he had engaged in a "show" to save the patient.

While traveling on the China Southern flight, Zhang－along with another doctor, Xiao Zhanxiang－learned of an older man who was unable to urinate and at risk of possible bladder rupture with six hours of flight time remaining.

Xiao made a makeshift urine draining device using a tube from an oxygen mask, a syringe needle, a straw and tape, but the urine did not automatically flow out via the improvised catheter because there was not enough of a pressure difference.

"There was not much time to use a big needle tube to siphon out the urine. In such an emergency, as a professional doctor, I had to siphon out the urine (by mouth)," Zhang said. Zhang repeatedly sucked out mouthfuls of urine over half an hour, spitting them into a cup.

With the urine drained bit by bit, the passenger gradually recovered. When the plane arrived in New York, the man disembarked safely with his wife.

Zhang, currently in New York for an international medical forum, will be honored and awarded for his "moral act" by his hospital, and his actions will be promoted, the hospital's publicity department said on Friday.

Meanwhile, Xiao, from Hainan General Hospital in Haikou, Hainan province, will be awarded 100,000 yuan ($14,200) for helping to save the patient, according to a report by news website The-Paper.cn.

"Xiao is a skilled, intelligent and courageous doctor in the style of famed Canadian physician Norman Bethune," it quoted Zhao Jiannong, Party chief of the Hainan hospital, as saying.