Police say there is a slim chance of finding a Mooloolaba fisherman alive after he went missing in calm waters off Queensland's Sunshine Coast on Monday.

Key points: The fisherman went into the water to check on the jet ski, which was taking on water

The fisherman went into the water to check on the jet ski, which was taking on water The man had taken off his lifejacket and disappeared when his friend tried to bring him to shore

The man had taken off his lifejacket and disappeared when his friend tried to bring him to shore A major search continued on Tuesday off Twin Waters but was called off at dusk

A major search resumed early on Tuesday morning for Luke Howard, 35, who disappeared as he was being towed back to shore while clinging to the back of a jet ski.

But no sign of Mr Howard had been found by the end of the day and the search was called off around dusk.

Mr Howard — who has been described as a fit person who regularly swam from Coolum to Mooloolaba and competed in triathlons — was fishing from the jet ski off Mudjimba with a friend, when the craft began taking on water.

Police said Mr Howard had gotten into the water to try and fix the craft but was unable to climb back on, and his friend tried to tow him back to shore while he clung to the back, but he disappeared from sight.

Sergeant Kyle Bates from the Water Police was on a boat searching for the missing 35-year-old this morning.

He said using tide modelling, the search area had been extended to a 20 kilometre part of the Sunshine Coast, stretching from Alexandra Headland to Coolum.

Friends describe Luke Howard as a fit, regular swimmer who competes in triathlons. ( Facebook: Luke Howard )

On Tuesday afternoon, Sergeant Bates said police could not use divers due to strong currents and the large search area, and chances of finding the man alive in the water were slim.

"Conditions are favourable, very flat conditions, which make visibility very good to us," he said.

"It was the same sort of conditions yesterday, which don't sort of indicate any chance that he would have been on the surface.

"We would have expected that with the amount of coverage we had that we would have sighted something."

Family and friends console each other on Twin Waters Beach. ( ABC News )

David McLean from the Marcoola Surf Life Saving Club said lifesavers were providing jet skis and boats, as around 30 volunteers combed the shoreline.

Members of the jet ski community have also joined the search.

"We have managed to get our drone up … we have done an initial search of the last known location," Mr McLean said.

"Basically it varies between the island and Twin Waters life guard station where the jet ski was beached."

Mr McLean said the friend who was driving the craft was devastated.

"The police have spoken to the gentleman concerned and he's quite distraught … he's been here the whole time searching for his friend as well," he said.

"They were good friends and as I said he's been distraught and we're all feeling for him and the family. "

He said the pair were well equipped when they set out on their fishing trip yesterday morning, but the missing man took off his lifejacket at some point.

"It's difficult to swim with a life jacket. He's either checking under the ski to see if the bungs were in and at some stage has taken the life jacket off and it's a terrible situation," he said.

Mr McLean said some of the 30 volunteer searchers had found items on the shore, including a t-shirt and GoPro camera, although neither were believed to be linked to the missing man.