A 61-year-old bird-flu patient from Hong Kong died Sunday after contracting the virus during a visit to nearby Guangdong province.

He was Hong Kong's third confirmed human bird flu case this winter, and the only fatality.

The patient is believed to have caught the H7N9 strain of avian flu after buying freshly-slaughtered chicken from a wet market across the border in the city of Dongguan, Guangdong province.

Another patient, a 69-year-old woman, remains critically ill in hospital. Over 150 human infections have been reported in the mainland since October.

Hong Kong's Secretary for Food and Health Ko Wing-man reminded the public to remain vigilant.

"If any citizens feel unwell after visiting the mainland, they must report to doctors on where they have been, and whether they have had contact with live poultry," Ko said.