The Prime Minister is hitting out at concerns over a tweet by her fiance Clarke Gayford.

Gayford has come under fire, after he wrote that an in-principle alert level decision was made, pending today's final test results.

Jacinda Ardern says she hasn't seen her partner since yesterday, and pushed back strongly on the implication he knew what the decision was.

"Clarke has not known the decision, he has known the process which is exactly what ministers have conveyed in the public domain."

Auckland's now joined the rest of the country at alert level one.