The NT Department of Education claims thirteen teachers have left Katherine High School since the end of the 2020 school year, with five positions still vacant.
In a statement, the department said thirteen is consistent with the average turnover of the past three years and also consistent with staff turnover at similar schools in the NT.
The department said three of the vacancies are new staff positions while the other two are existing positions which are yet to be filled.
This year is an improvement on the beginning of 2020, when the school had to replace more than 20 teachers.
Eleven teachers left the school at the end of 2018.
Australian Education Union NT branch president Jarvis Ryan said he expected more teachers to leave Katherine at the end of last year.
"There was predicted to be very high turnover at the end of last year," he said.
Mr Ryan said it isn't always possible to have a full staff ready for the new year in schools like Katherine High School due to the remote location.
He said there is still time for the positions to be filled before term starts on February 1, but they shouldn't be left empty for much longer.
"School doesn't start for close to three weeks... they would still be in the recruitment process now," he said.
"It's getting fairly late if there isn't at least a verbal commitment from someone.
"Ideally you want every school to have it's full staffing compliment on day one but in some cases that is not achievable when you're trying to relocate someone from thousands of kilometres away."
Mr Ryan reasserted the union's view on how to fix the ongoing vacancy and staff turnover problem.
He said the NT Government should reinstate the rental subsidy program and offer permanent employment to teachers in Katherine.
"Our view as a union is that the department should certainly be doing more to attract teachers with offers of permanent employment," he said.
"The phasing out of the previous housing subsidy, that may well be contributing to difficulties they're having in recruiting teachers."
He said the rental allowance, which is given to new recruits instead of the subsidy, is not doing enough to attract teachers to the town.
"Teachers I speak to in Katherine, some of the feedback we've had is it's certainly not helping."
NT Education minister Lauren Moss told the Katherine Times last year staff retention would not be a problem in 2021.
"I think retention has been an issue in Katherine for some time," she said at the time.
"The school is in a very good position for 2021, and a better position than it may have been in previous years."
Ms Moss was speaking in relation to a commitment of more than $200,000 to improve Katherine High School's infrastructure and staffing levels.
Mr Ryan welcomed the commitments and credited the local community with pushing the government to take action.
"The good thing you've got in Katherine is you've got a lot of very vocal parents. The community is invested in making sure their school is successful," he said.
"There's been a concerted effort to make sure the government and the department understand the challenges (in Katherine)."
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