A number of children injured in the jumping castle tragedy in Tasmania were reportedly enclosed in Zorb balls as police continue to investigate what led to the death of five primary school students and three others fighting for their lives.

A jumping castle at Devonport's Hillcrest Primary School was lifted into the air while Zorb balls — a large inflatable ball that a person can climb inside of — were also picked by a strong gust of wind.

Nine children fell about 10 metres, fatally injuring three boys and two girls. One was 11 years old and the others were 12. Three children remain in hospital in a critical condition.

During a press conference on Friday, Tasmania Police declined to say if the jumping castle had been tethered to the ground at the time.

“That forms part of the investigation. We need to continue our investigation on behalf of the coroner as well as WorkSafe Tasmania,” Police Commissioner Darren Hine said.

“We all have a lot of questions and we need to form that as part of the investigation.”

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When asked if the Zorb balls were inside or outside of the jumping castle at the time of the accident, Comm Hine said that will also be checked out by authorities.

“That will form part of the investigation, but my understanding is that the Zorb balls were outside,” he said.

Some of those injured were in enclosed plastic Zorb balls, according to The Age.

Comm Hine said it was fair to say the injured children were inside the jumping castle at the time.

Police have said a “significant local wind event” contributed to the tragedy.

Witnesses described seeing the jumping castle reach 10 metres into the air.

According to data from Devonport Airport, wind gusts hit peaks of 33km/h on Thursday.

At 9am, just prior to the incident, wind speeds reached 13km/h before increasing to 24km/h about 3pm, the Bureau of Meteorology reported.

Tragedy rocks Devonport community

Hillcrest Primary School was holding a 'Big Day In' celebration to mark the end of the school year, with about 40 children in attendance, police said.

Several adults were also hurt when the bouncy castle was lifted.

"There is no doubt this incident will leave its mark, and I know people are sending their thoughts and prayers from right across the country," Comm Hine said in Devonport on Friday.

People gathered outside the primary school on Thursday night for a candlelight vigil and flowers, and messages of sympathy have been left near the gates.

Mourning locals turn Christmas lights off

Some residents turned off their Christmas lights as a mark of respect.

"People who just have no connection to the school, or any of the families, have just come in crying and grieving over the loss of the children in something that was supposed to be a celebration," Fiona Morrison, a member of the local Uniting Church, told Nine Network.

"They just can't believe what has happened.

"Last night, people turned off their Christmas lights in respect, or turned on their Christmas lights to offer the other children some hope, some light, at this time when they are grieving."

With AAP

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