Concerns have been raised about the Northern Territory's new law requiring tens of thousands of workers be vaccinated against COVID-19 by Christmas.
The new health directive makes it mandatory for most workers who interact with the public to be fully vaccinated by December 24.
Those who don't could be fined $5000 and banned from entering their workplace.
The mandate is part of the NT's virus management plan to protect Territorians once border restrictions and quarantine rules are relaxed next year.
But the Australian Education Union NT is concerned the vaccine mandate could lead to staff shortages in schools.
A survey of more than 640 school staff across urban and remote areas revealed 17 per cent of teachers don't intend to get vaccinated.
The survey also found that 33 per cent of respondents don't agree with mandatory vaccinations for school employees, and 11 per cent had mixed feelings.
"Whilst it's a minority view, there is a significant proportion of members who aren't supportive," branch president Jarvis Ryan said Thursday.
It could impact staffing levels if workers are forced to resign or are sacked because they refuse to get the jab.
"Our schools are already stretched and we have members saying they're adamant they won't get vaccinated," Mr Ryan said.
"We may lose some very capable employees."
The union has written to members advising any who are unvaccinated to book an appointment immediately.
It warned that "failure to comply with the mandate would likely lead to termination of employment".
The NT police union says about a third of officers are unvaccinated and it would assist any that refuse to comply with the health edict.
"The safety, health and wellbeing of our members will always be the primary focus of the NT Police Association," president Paul McCue said.
"Those who are unable or are unwilling to get vaccinated will be guided through the process with the department on a case-by-case basis."
The NT Police Association estimates about 70 per cent of the NT Police Force has had one dose of the vaccine.
Senator for the NT Sam McMahon said the NT government had gone too far and the new law was among the toughest in the world.
"This is a massively heavy-handed approach - we are in Australia, where the federal government has refused to make vaccines mandatory," she said.
"From the announcement you could be forgiven for thinking we're living in Nazi Germany, not the NT."
Dr McMahon said similar laws mandating the vaccine for police and aged care workers were being legally challenged in NSW and Victoria.
"(The NT government) should wait until the results of those cases are handed down before making such sweeping decisions, affecting the lives of thousands of Territorians."
The new health rules allow employers to demand proof of vaccination from staff and to keep information on those who have had the jab.
Opposition health spokesman Bill Yan said the requirements would be an additional burden on understaffed territory businesses.
He described it as a draconian measure that required "pretty well the entire population of the territory to be vaccinated".
"If the government had been doing what it should have been doing over the last 18 months, we wouldn't be in the position where we have the most severe measures in the world for vaccinations," he said.
"And we wouldn't see these issues placed on business to try and manage."
Australian Associated Press