Emergency services were called to Fishing Point at Rathmines about 6.30pm on Saturday after a three-year-old boy had been pulled from the water unconscious.

Bystanders gave the child first aid until paramedics arrived but the child could not be revived and died at the scene.

Lake Macquarie police attended the scene and are making inquiries, and will prepare a report for the coroner.

It was one of three tragic water incidents on Christmas Day, with the search for a swimmer missing at Bathurst resuming this morning, and another at Albury.

A man at Bathurst went missing while swimming in a dam about 1.30pm. He was with a group of people on a boat on the dam when he told his friends he was going to swim to shore, a distance of about 300m.

A storm struck the area a short time later and the man's friends saw him disappear under the water.

Emergency services were called and a search began involving officers from Chifley Police District, local Police Rescue, and multiple SES craft.

In Albury, a teenager went missing while swimming at about 2.15pm in the Murray River. He was with several teenage boys in the river at Noreuil Park when they got into difficulties.

They were helped from the water, however, one person was unaccounted for and emergency services were alerted.

A joint multi-agency search to locate the missing youth was initiated involving officers from Murray River Police District, NSW Ambulance, members of the Volunteer Rescue Association (VRA) and State Emergency Service (SES), and drone operators.