According to sources, the last known location of their cellphone signal was on Sai Sha Road.

The 61-year-old Lung Chun-kau and 18-year-old Lung Kin-tai were missed after leaving their apartment at Tseung Kwan O on Saturday at around 10 am.

The police received a report from a woman who reported her husband and son had not returned after heading to Sai Kung to take a hike and were worried they had run into any accidents. 

However, she could not provide further information as she did not know their route.

After receiving the report, the police and the fire department arrived at Tseng Tau Tsuen and started their search, with an ambulance standing by at the site.

Lung Chun-kai is 160 cm, 50kg, with an average body type, round face, yellow skin, and short white hair. He wore a dark grey jacket, dark grey long pants, dark grey sneakers and a white cap when he was last seen. He also carried a black and blue backpack.

His son is 170cm tall, weighing 80 kg, with a chubby body type, round face, yellow skin, and short black hair. He was last seen with a dark grey-sleeved shirt, green pants and green sneakers. He also carried a camo-coloured backpack.

The police urge anyone who knows of the father and son's whereabouts to contact them.