A sixth child has died following the jumping castle tragedy that has devastated a Tasmanian community.

Chace Harrison’s life support was turned off four days after the 11-year-old was hurt during end of year celebrations at Hillcrest Primary School in Devonport.

His death on Sunday followed the loss of 11-year-old Addison Stewart and 12-year-olds Zane Mellor, Jye Sheehan, Jalailah Jayne-Maree Jones and Peter Dodt.

Two children remain in a critical condition in Royal Hobart Hospital.

On Sunday, grieving relatives visited a memorial site at the school and spoke of their grief as they explained it would be impossible to celebrate Christmas this year.

The grandfather of Zane Mellor hugged a tree at the scene where his beloved grandson had been killed. Zane’s mum Georgie Gardam had also returned to the school at the weekend.

“This isn’t real, how do we go on without you,” she wrote in an online tribute to her son.

“We know we gave you the best life, I may of let you game a little too long or spoilt you with too much McDonald’s and Hawaiian pizza and buy too many playstation games but everything I did in life was for you.

“I have let your online friends know you won’t be back online to smash them in fortnite [an online game] for a while….my world is broken.”

Addison Stewart’s grandparents, Graham and Sharyn Deacon, remembered how they last saw their “beautiful” granddaughter just days before the tragedy when they watched on with pride as the grade five student received school awards and found out she had been named a 2022 class leader.

Twelve-year-old Beau Medcraft, who has been released from hospital, came to the school to pay tribute to his classmates.

The survivor, with arms in bandages and a sling, was supported by family and police as he returned to the place where a gust of wind caused the jumping castle he was playing on to be thrown 10 metres into the air.

In a touching tribute to his game-loving friends, Beau left video game controllers at the memorial site where hundreds of other mourners have lay flowers and teddies.

Beau’s father, John Medcraft, said his family was “somehow so blessed…to be somehow so unbelievably lucky” that their child survived.

“We are so so deeply sorry for all the other parents,” Mr Medcraft wrote on Facebook, adding that he and wife Tammy’s “hearts break” for the other families.

He said Beau was “bruised and busted and broken”.

“But he’s still with us… he’s more thinking of his mates he’s lost and all of them,” the dad wrote.

Police Commissioner Darren Hine confirmed the death of Chace on Sunday afternoon.

“It is with a heavy heart that I can confirm a sixth child has lost his life following the tragedy,” Mr Hine said in Hobart.

“An 11-year-old boy died this afternoon. His name is Chace Harrison. Our thoughts continue to be with his family and all other families and loved ones of the children involved.”

The state’s top cop said the investigation into the incident in conjunction with WorkSafe Tasmania was ongoing and would be for some time.

“We are working tirelessly with all parties concerned to ensure the extensive investigation is completed as a matter of priority for the coroner,” he said.

“Their priority will be to interview all witnesses, gather and analyse forensic evidence at all in biomedical aspects including weather patterns and conditions of the time of this incident.”

Given the magnitude of what happened and the need to speak to a large number of traumatised children within a short period of time, Tasmanian detectives have accepted an offer of help from NSW police.

Four forensic child interviewers will travel to the island state from Sydney over the coming days.

“I am certain all Tasmanians share with me a deep sadness and heartache that young Chace Harrison, another child involved in this terrible tragedy, has now passed away,” Premier Peter Gutwein said.

“I know that our community, which is so connected, will be deeply saddened, for the family involved and indeed all the families of the now six children who have lost their lives.”

On Saturday, Prime Minister Scott Morrison announced an extra $800,000 will also be made available to fund trauma counselling for those impacted.

Some $250,000 will go to first responders involved in the aftermath of the accident and $550,000 to the broader community.

More than $1 million has also been raised in the community to support those mourning the tragedy.

• Lifeline: 131 114
• Kids Help Line: 1800 551 800

-with AAP