Only essential visitors and no children visitors are now allowed by the Canterbury District Health Board at all its hospital sites following an RSV outbreak.
This follows many health boards in the North Island making the same call in recent weeks.
There has been a sharp increase in the number of RSV hospital presentations since the travel bubble was opened to Australia in April.
The board said it had made the visiting changes due to the ongoing high levels of respiratory illness in the community.
"This is to reduce the risk of illness spreading to and among our most vulnerable patients, particularly those in maternity, NICU and other child services, and ICU," it said.
It was limiting visitors to just one at a time, but would allow an additional support person for someone with a disability.
The board said newborns and children have a higher risk of catching RSV and becoming severely ill.
Hospitals across the country have postponed surgeries and are creating extra bed space for children as they deal with a sharp surge in the highly contagious winter virus.
At Starship, children under 14 are not allowed to visit loved ones.
The latest ESR data showed weekly visits to the six main hospitals spiked to a total of 2543 this year.
Last year, just 34 RSV cases were recorded between April to September.
MidCentral DHB urged anyone experiencing cold or flu symptoms, or symptoms of respiratory illness, to seek a Covid-19 test.
Anyone who was feeling unwell was encouraged to stay home and maintain high standards of personal hygiene, including coughing into their arms and regularly washing and sanitising their hands.
"If you require medical attention from a GP, please remember to call the practice first.
"Free medical advice can also be sought by calling Healthline on 0800 611 116."