A Myanmar national sustained serious injuries in the stomach after he was stabbed and then thrown into the sea at the Tan Jetty, Weld Quay, here last night.

Timur Laut District Deputy Police Chief Supt Ismail Idris said the man, in his 30s, was rescued by members of the public after he was seen struggling to swim to shore during high tide in the 11pm incident.

"We believe the victim was stabbed several times with a sharp object and is now being treated at the Penang Hospital," he told reporters here Sunday.

He said the motive of the attack was still being investigated, but initial investigations found that two unknown individuals had fled the location prior to the incident.