The ban took effect on Monday and could be in place for up to 14 days but would be reviewed every 48 hours.
In a statement, INZ general manager Catriona Robinson said there may be some foreign individuals who had left or transited through mainland China that have exceptional circumstances who may be granted entry permission into New Zealand.
This would be determined on a "case by case basis".
Robinson did not reveal how many people had been denied entry since the restrictions came into force.
"If an individual arrives in New Zealand from mainland China and is refused entry, the airline who has brought the passenger to New Zealand will be liable to remove the passenger back to their port of origin," Robinson said.
Asked who would pay if a passenger was denied entry, Robinson said it depended on their visa status.
"If the passenger who has been refused entry holds a visa, Immigration New Zealand is responsible for covering the cost of removing them back to their port of origin. If the passenger does not hold a visa, the airline is responsible for covering the cost."
New Zealand citizens, permanent residents, residents with valid travel conditions and their immediate family are all exempt from the new travel restrictions.
Australian citizens and permanent residents were able to enter if their primary place of residence was New Zealand, INZ said.
All individuals arriving in New Zealand who have been in mainland China in the last 14 days are required to self-isolate according to the Ministry of Health guidelines.
Foreign travellers in transit to New Zealand on February 2 would be subjected to enhanced screening but pending clearance, granted entry.
All the passengers arriving later today on the chartered Air New Zealand flight from Wuhan — effectively ground zero for the coronavirus crisis — will spend 2 weeks in isolation. They will be taken directly from Auckland International Airport to a military facility at Whangaparāoa.
Customs closed its eGates at New Zealand airports and all incoming passengers are now being manually processed.
The closure of eGates also includes New Zealand citizens, permanent residents and their families, with passengers urged to be patient.
In the statement, Customs said there would be operational impacts and it was looking at how to best support its staff and minimise disruption for travellers.
Customs was constantly reviewing and complying with advice from the Ministry of Health amid the outbreak.
If frontline staff were working within close proximity of a passenger, going to be dealing with a passenger for longer than 15 minutes or if the passenger had come from mainland China, they were required to wear a mask and gloves.
"There are a range of protective hygiene and infection control processes, of which wearing masks is only one," Customs said.
