Police hold grave fears for 26-year-old Jordan Kelly who became separated from his mate Jack McDonald while they were paddling their surf skis around North Stradbroke Island on Saturday.

McDonald has told police they paddled for hours getting nowhere in one of Queensland’s most treacherous sand bars.

Both ended up in the water when McDonald’s ski started to sink. The 28-year-old has told police his friend Jordan “slipped away” after exhaustion set in.

McDonald was able to paddle to safety, making it to Amity Point Wharf on the island at about 8pm, about seven hours after they got into trouble.

On Monday, police could not confirm media reports that the second ski had been found in the ocean.

The search is continuing with the assistance of a helicopter and a dozen vessels. Other teams are checking the shorelines of North Stradbroke and nearby Moreton islands.

Members of Kelly’s family have arrived from New Zealand, with others on their way.

Police have shared McDonald’s account of what happened.

He told authorities they set off from Dunwich, on the mainland side of the island, and intended to paddle around the top of the island to Cylinder Beach, on the ocean-facing side before heading back again.

But about 1.30pm on Saturday, McDonald’s ski started to sink.

“Jordan has paddled over to assist him. They’ve both held onto that ski until such a time, after dark, that they’ve just become weak and tired from being in the water and unfortunately Jordan slipped away,” Acting Senior Sergeant Mitch Gray said.

The men were not wearing life jackets and sea conditions on the exposed side of the island were hazardous, he said.

“As time goes on, certainly we become more and more concerned we’re not going to have a happy ending to this scenario.”

Gray said eight boats and four jet skis resumed the search for Mr Kelly early Monday morning.

“Today we’ll be looking from the tips of Moreton Island … from the northern tip to the most southern tip, and we’re looking inside the bay and certainly offshore as well.”

He said McDonald had a “traumatic” experience on Saturday and had described his ordeal to police.

“Jack’s upset. He’s very concerned for his friend, as are we,” he said.

“They fell off a number of times, then Jack’s actual surf ski started taking on water.

“Jordan’s paddled over to help him and they’ve ended up just sort of hanging on to Jordan’s ski.

“[With] hypothermia, cold temperatures and the water, it’s extremely difficult to hang on to objects.”The colder you get your physical functions of your hands and things become difficult to utilise.

“At some point, you know, Jordan’s let go of the ski, and they’ve drifted away and when Jack could no longer see him, he’s gone for help, and paddled as fast as he could back to Amity Point.”