THE memory of charging up the broad sandy strip of Maroochydore Beach as a 16-year-old to win both the junior and senior national ironman titles still burns brightly for Grant Kenny.

He can't imagine what it would be like to emerge from the breakers to see a rock wall jutting out of the Maroochy River mouth at Cotton Tree.

"It would be an absolute disaster," was how the surf lifesaving legend described it.

He is one of the latest to come out against a proposal to replace the sandbags at Cotton Tree with a rock wall, making his position clear in a video for community group Don't Rock the Maroochy.

"I totally disagree with what the council's contemplating doing with the river mouth," Mr Kenny said.

"I think it'd be dangerous and it'd be taking away a great playground for kids."

He recalled growing up as a kid, the river mouth sitting to the north of Pincushion Island, keeping Maroochydore Beach flush with sand.

"Pincushion historically has been a good anchor, in effect a natural groyne to allow that sand to build up," he said.

"Those memories (childhood) are of a very healthy stretch of beach between Alexandra Headland and the Maroochy River mouth."

Mr Kenny said setting aside the emotional and scientific arguments, he saw little sense in replacing what was currently a family-friendly structure with rocks.

"It's (rock wall) not family friendly at all," he said.

Meanwhile the wait continues for the Maroochy River Estuary Consultation Group to be finalised.

The group was originally due to be constituted in June, but the group is close to forming, with the chairperson appointment being finalised at present.

An update provided by Division 8 Councillor Jason O'Pray said standing members, including state agencies, surf clubs and the university had all agreed to participate.

Twelve nominations for non-standing member positions had been received and a cost-benefit analysis had also been completed and was ready for presentation at community consultation.

All applications for positions were being reviewed by the group chair, a council staff member and a representative from the Mayor and CEO's office as part of a three-person panel assessment process.