Health authorities have banned running in managed isolation and quarantine (MIQ) facilities, to the frustration of some returnees.
A rule introduced last month prohibits any exercise that creates heavy breathing or perspiration while returnees are out of their rooms - limiting them to light exercise like walking instead.
The Ministry of Business, Innovation and Employment said it was due to the virus being transmitted by tiny respiratory particles.
In exceptional circumstances, returnees can apply for approval for heavy exercise from MIQ headquarters in consultation with health specialists.
Andrew Bank was doing step-ups during a one-hour exercise session at the Novotel Christchurch when he said a security guard intervened, asking him to stop.
He said the new rule seemed like overkill given he was vaccinated and wearing a mask, so he had filed a complaint.
"I would expect in quarantine they would at least afford you the opportunity to leave your room and get some exercise aside from the small little cramped hotel rooms," he said.
"I was a little shocked and disappointed to learn we can't do any type of exercise that would elevate our heart rates to stay well and keep ourselves fit while quarantining."
He said there was a large amount of space in the exercise area, and returnees were already divided into cohorts.
"I don't need anything too fancy here. I think just something with a little bit of space where we can stretch our legs, get a light jog in, get a little sweat in."
In a statement, the ministry said returnees at the Novotel could hire an exercise bike at their own cost, and have it delivered to their room.
It was unclear what was available at other MIQ hotels.
The tightened rules follow the introduction of a booking system for exercise in February.
People doing exercise are still required to wear a face mask and maintain 2 metres physical distancing, while returnees from high-risk countries are banned from leaving their rooms until they receive at least one negative test.