Two dead after boat capsizes in Moreton Bay, east of Brisbane

Two men have died after a boat overturned in waters off Manly Boat Harbour, east of Brisbane.

The small vessel capsized in Moreton Bay between North Stradbroke Island and Green Island.

The incident was reported about 1.37pm.

One man died at the scene, another was transported to the Princess Alexandra Hospital in a critical condition and later died.

Acting Inspector David Candale said the two men were yet to be identified.

Video from the scene showed specialist police divers jumping in to the water and the South Passage training ship nearby.

It is understood passengers onboard the South Passage saw the incident as it unfolded and rendered first aid.

"We believe a boat that was passing by had observed that the boat had overturned," Insp. Candale said.

"They immediately stopped and rendered assistance to one of the males and pulled that person from the water.

"A call for assistance was put out via radio.

"As you could imagine, certainly witnessing an event like this would be distressing for anyone."

Insp. Candale said he believed the men were on the water fishing.

He issued a word of caution against going out in windy conditions.