Two separate incidents occurred at the Bogey Hole in Newcastle about 3.30pm yesterday.

A 13-year-old boy slipped and hit his head at the popular swimming hole about the same time as two men, believed to be in their early 20s, were swept out to sea.

The men had been jumping off a ledge at the Bogey Hole.

One was able to swim to shore. The other was rescued by a lifeguard from Newcastle beach on a jet-ski.

An ambulance service spokesman said the 13-year-old was treated at the scene by paramedics and taken to John Hunter Hospital in a stable condition.

Two near drownings also occurred at Glenrock Lagoon, near Newcastle, and Zenith beach, at Shoal Bay, yesterday.

A 13-year-old boy was rescued and taken to hospital after getting into difficulties at Glenrock Lagoon.

At Zenith beach, the Westpac rescue helicopter was called after a man in his 40s was pulled from the surf and treated at the scene, but did not require transport to hospital.

Surf Life Saving Hunter branch president Henry Scruton warned swimmers to be vigilant.

He said people should stick to basic rules like always swim with a friend, swim between flags and be aware of changing surf conditions.

The Bogey Hole has claimed two lives in the past decade.

Nathan Luke, 26, of Gateshead, died after he hit his head on a submerged rock there on January 26, 2010.

A 41-year-old man died after he was washed off rocks by a wave while washing his face at the bathing pool in 2003.

There had been fears the Bogey Hole would close due to safety concerns.

The NSW Heritage Council has granted approval for rejuvenation and safety works to improve the swimming hole, with work expected to be completed by mid-year.

The state government has awarded a $360,000 tender to a Sydney company for the works that include a new stairway and access platform.