Redland Bay police search for missing surf-skier continues off North Stradbroke with a fleet of vessels on the water in rough conditions.

Mr Kelly failed to return to Cylinder Beach after a mid-morning surf ski expedition with a friend on Saturday.

Police and Coast Guard are combing Moreton Bay under bleak and cold conditions, with help from a helicopter and about a dozen vessels while other teams are checking North Stradbroke and Moreton Island beaches.

Mr Kelly and his friend, 28-year-old Jack McDonald, were kayaking from calm water at Dunwich to the exposed Cylinder Beach when the two were forced into the water in rough swells.

Mr McDonald told police the men ended up in the water when his ski started to sink, and Mr Kelly came to help. He slipped away after exhaustion set in.

Mr McDonald paddled to the Amity Point Wharf about 8pm Saturday night and was taken to Marie Rose Hospital at Dunwich in a stable condition but suffering from hypothermia.

Air and search rescue crews worked through the night, and the search was expanded at first light as rough surf conditions continued on Sunday.

Acting Senior Sergeant Mitch Gray said the men were not wearing life jackets and the passage of water they chose to explore was one of the most dangerous bar crossings in the state.

He said the search and rescue mission would continue until at least Thursday.

Mr Kelly's family had arrived from New Zealand to help with the search on land.

"As time goes on, certainly we become more and more concerned we're not going to have a happy ending to this scenario," Sergeant Gray said.

Emergencies services were stretched across south-east Queensland on the weekend, with multiple incidents.

Two men were rescued from their stranded jet ski off Russell Island by a northern NSW chopper called in to help out on Saturday night and another two were saved by the Bundaberg-based RACQ LifeFlight Rescue helicopter after their boat was swamped in rough conditions.

A third nearly drowned after his boat flipped while trying to cross the Maroochy River bar on the Sunshine Coast.

RACQ LifeFlight Rescue choppers from Brisbane and Toowoomba airlifted three motorcyclists to hospital on the weekend following separate crashes in the Scenic Rim.

A motorcyclist was killed in the South Burnett region while an 18-year-old man was killed when he was thrown from a 4WD on Ocean Beach at Bribie Island on Sunday.

Last month a 21-year-old man disappeared from his tinnie, presumed drowned in Moreton Bay near Mud or Green islands.

The incidents have occurred after warnings from police and Coast Guard about people venturing out in unsafe conditions, or trying to travel too far on the potentially dangerous Moreton Bay in small craft like dinghies, jet skis, kayaks and canoes.