Premier Campbell Newman offered his condolences to Matt's family.
He said there may be a need for a broader inquiry, but made no promises.
"My condolences and the condolences of all Queenslanders go to his parents,'' Mr Newman told reporters in Brisbane.
He said if there needed to be a further inquiry, beyond a coronial inquiry, he would look to that in the days ahead.
The promising youngster had been hand-picked for Surf Life Saving Queensland's Future Champions in 2010, training alongside stars including Elizabeth Pluimers and Kristyl Smith, the website said.
The incident followed a tragedy that struck surf life saving two years ago, when 19-year-old Saxon Bird died during the same carnival at the same beach and under chillingly similar circumstances.
Surf Life Saving Australia CEO Brett Williamson said it is too early to confirm reports the boy was knocked from his board and didn't surface.
"There are various reports coming in; all that will be collated and reviewed in due course,'' he told reporters.
Police regional duty officer, Inspector Geoff Palmer, said after a fruitless search on Wednesday afternoon hopes of finding the boy alive have faded.
Mr Williamson said conditions had been closely monitored through the day and a number of events had been modified, postponed or relocated to still-water venues.
The decision not to call off the junior competition would be reviewed in due course.
"We are confident from a surf life saving perspective that all our risk-management systems and decision-making processes were very robust and in place.
"But that, no doubt, will be subject to external reviews."
Mr Williamson said while the surf was not ideal, the swell was not as large as it was two years ago when Saxon Bird died after an accident in almost the same spot.
"The swell through the day fluctuated between point eight (of a metre) to just over one metre.
"Our thoughts and prayers are obviously with the family, and the broader surf life saving membership,'' he said.
Wednesday was the first day of official competition in The Aussies, with final events scheduled on Sunday.
- AAP
