"The medical ward at Dunedin Hospital had a Covid-19 exposure event last week and, as a precaution, mask wearing and Rat testing of staff was introduced to prevent any potential spreading," Dr Gow said.
"The source of the exposure is unknown.
"The precautions are being reviewed daily and will likely stay in place until after this weekend."
The medical ward is also known as ward 8.
Te Whatu Ora Health New Zealand (HNZ) said there were 354 active Covid-19 cases in the southern region.
University of Otago epidemiologist Prof Michael Baker said this wave of Covid-19 had been more "prolonged and persistent" than the third and fourth Covid-19 waves earlier last year.
"What started off slowly has become quite big, and we’re seeing the effects of long Covid-19 on many patients.
"Covid-19 is far from over."
Prof Baker said the government needed to step up its vaccination drive for at-risk groups and improve public communication about the risk of respiratory infections.
"There really needs to be a respiratory infectious disease strategy," he said.
"We have actual prevention methods that are already in place, such as vaccination, self-isolating when sick, improving ventilation in indoor areas, and wearing a mask if immuno-compromised.
"We just have to work hard to ensure these methods work."
Support for self-isolation of infected cases could include improving sick leave entitlement, he said.
"The Covid-19 subvariants appear to be evolving in ways that create a heightened risk of re-infection, particularly among immuno-compromised," Prof Baker said.
"The most recent subvariants are as different as Omicron was from Delta."
He said HNZ Southern’s approach to the latest Covid-19 wave was understandable.
"They need to be deliberate and systemic in their approach.
"There is a risk we are becoming complacent about Covid-19, so it’s about having a plan of action."
