Commemorations marking the one-year anniversary of the accident will be held in the northwest city of Devonport on Thursday and Friday.
Six children enjoying end-of-year celebrations on the school's oval were killed and three others badly injured when a wind gust picked up the castle and several inflatable balls.
There were 174 emergency services workers, either at the scene or in radio rooms, involved in the immediate response.
Director of wellbeing support for the state's emergency services, Matthew Richman, said about 12 had not returned to work.
"As we saw through the flowers that were left at the scene ... it was a really impactful event for the entire community," he told reporters.
"All the emergency responders are part of that community, and it was felt very strongly."
Mr Richman said professional support was immediately provided to emergency personnel and it has been extended for a two-year period.
He said the support process had entered a second phase, which includes regular wellbeing checks.
"It's well-known the earlier the intervention can occur, the better the outcome will be over time," Mr Richman said.
A joint coronial inquest, which is yet to set a date for public hearings, will examine the circumstances surrounding the deaths of grade five and six students Zane Mellor, Peter Dodt, Addison Stewart, Jye Sheehan, Jalailah Jayne-Maree Jones and Chace Harrison.
Members of the public are invited to leave a message of support at Devonport's Market Square from 5.30pm on Thursday.
The school is holding a private commemoration on Friday, marking exactly one year since the tragedy, while plans for a permanent public memorial will be progressed next year.
More than $1.4 million was raised for the families of the victims and countless messages of support and flowers were left outside the school.
"It is important from time to time for the public to put themselves in the shoes of the responders (and) understand the complexity and the magnitude of what is being dealt with," Mr Richman said.
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