The Advocate has asked Te Whatu Ora Te Tai Tokerau (previously the Northland District Health Board) for information about how many patients in the ward have tested positive.
The remainder of the hospital remains open to visitors and the visitor policy for the general ward will be reviewed on Thursday.
"This reminds us that Covid-19 remains an issue in our community, and people should remain vigilant," she said.
A ward closure was often triggered by a spike in a contagious virus or infection in a localised area and in most years were sparked by outbreaks of norovirus and influenza.
Thomas advised people to wear masks, socially distance, frequently wash hands, stay home if unwell, get tested, and seek a full course of Covid-19 vaccinations.
"Everyone is asked to not visit a Northland hospital if they are unwell, and all visitors must wear a mask throughout their visit."
"While most people who are healthy and vaccinated will have a milder illness, Covid-19 is potentially more dangerous for people who are unwell and already in hospital."
Last Friday an increase in patients testing positive in Whangārei Hospital's Ward 1 meant people were prohibited from visiting the ward.
The ward remains closed to visitors until Thursday when the policy is to be reviewed.
News of the two outbreaks in Northland hospitals comes as Te Whatu Ora Te Tai Tokerau continues to warn communities about the "significant community spread" of Covid-19.
The region recorded 247 new cases of the virus in the 24 hours up to 6am on Tuesday. Of those, 136 cases were in Whangārei, 80 in the Far North, and 31 in Kaipara.
Overall, there are 1500 currently active cases in Northland - 14 of whom are in hospital. More than 44,000 people have recovered from the virus in Tai Tokerau.
The Covid death toll in Northland sits at 62 from a total 1803 nationally.
