The new cases bring the total to 53 confirmed, and four probable.
The locations of the new cases are; four in Wellington, one in Taranaki, three in Auckland, one in Waikato, one in Taupō, one in Manawatu and two in Nelson.
Three of NZ's confirmed cases are in hospital and all are a stable condition.
One man in his 60s is in Lakes District Hospital in Queenstown, a woman is in hospital in Nelson and another person is in North Shore Hospital.
"Most of these cases are travel-related but as yet, in two instances, no link to overseas travel has been ascertained and we continue to investigate," Bloomfield said.
"We always knew that cases apparently not linked to travel would happen and we are prepared for that."
Of the new cases in the past 24 hours, Bloomfield said the two cases not linked to travel are one in Auckland and one in Wairarapa.
The person in the Wairarapa is symptomatic, which is why the clinician decided to test, Bloomfield says.
They are now investigating whether these people have had close contact with anyone who has travelled overseas, he said.
"In the case of the Wairarapa [person], we can't rule out the risk of community transmission."
Physical distancing is fundamental to our collective response, he said.
He reminded people that gatherings larger than 100 people indoors and 500 people outdoors should not be taking place.
Bloomfield said testing had ramped up as practitioners have identified people who needed testing. Yesterday, 1500 people were tested.
It is now more important than ever that we continue to track and trace individuals who may have been in contact with confirmed Covid-19 cases and get those people in self-isolation so that we can contain any further spread."