The move comes after the auditor general raised concerns about fire protection at other bases.
John MacLellan, president of the national union of defence employees, says it will mean job losses.
"Certainly it will affect people that do work, such as our plumbers who take care of the booster pumps for our water systems, it'll take care of our electricians who take care of the alarm systems, our firefighters — there's 450 firefighters across Canada," he said.
CFB Gagetown is already dealing with at least 145 layoffs.
The auditor general found 84 per cent of bases were not complying with fire safety rules.
But CFB Gagetown has passed its fire safety audits in the last few years, said local union president Morris Shannon. Still, its services may be privatized anyway, he said.
"When we asked the question, were we going to be exempt from this because we have done our work, the answer we got back unfortunately was you may all be lumped in the same group," Shannon said.
“Request for information was sent out before we even knew that they were even looking at this," he said.
"If there are issues, why was it not brought forward and discussed with us as to what the issues were and maybe what the direction they were taking was to fix it.”
A spokesperson for the Department of National Defence stressed that the government is just weighing its options and no decisions have been made about outsourcing fire protection.
At least 145 civilian employees at CFB Gagetown received letters last week, stating they may lose their jobs as a result of the federal government's cuts to the Department of National Defence.
It was announced in April that New Brunswick would lose more than 120 Department of National Defence civilian jobs as part of federal cuts across the country. At the time, it was believed Gagetown would lose 98 positions.
The total number of people who will lose their jobs is still unknown.