Police are searching for two teenagers after one of them told a police officer he was infected with Covid-19 and spat in his face.
The officer will now have to spend the next fortnight in self-isolation.
The incident took place in Rangiora this afternoon.
The two boys, both aged about 14, had been seen riding BMX bikes near Dudley Park at 3.20pm, police said.
"When the pair were being spoken to by Police one of the males stated that he had COVID-19 and then spat in the face of the officer.
"As a result of this assault the officer will no longer be able to perform his duties within the community and will be in self-isolation for 14 days from his family," police said.
Such behaviour was extremely concerning and dangerous.
"Police staff should not be targeted in such a way and we need to ensure the community is safe from such behaviour."
Police Commissioner Andrew Coster revealed this afternoon that eight officers had been spat at by members of the public.
The act was considered an assault and was punishable with 14 years in prison, he said.
Anyone who spat deliberately on others was "thoughtless" and "malicious", he said.
"It is completely unacceptable."
One of the two Rangiora teenagers had long brown hair and was wearing grey clothing and a black cap.
Earlier this week, a Christchurch man who filmed himself coughing on supermarket shoppers has admitted offensive behaviour - and apologised for his "foolish act".