Earlier, their spokeswoman said conditions on the water “are challenging due to swell and darkness”.
The alert was raised with police after the pair got into trouble just before 6pm. One swam ashore but the other remained missing, the spokeswoman said.
Three Coastguard vessels were on the water searching, including from Coastguard Titirangi and Coastguard Papakura. The Herald understands the Waikato Westpac Rescue Helicopter was also involved.
Auckland International Airport’s hovercraft was also on the water.
Coastguard’s spokeswoman said: “Our thoughts are with the whanāu of the missing individual during this challenging time.”
She referred all further questions to police.
Police said they were called to the harbour at about 5.50pm. A spokeswoman confirmed one person had been found safe and did not need medical attention.
The Herald has approached Waikato Westpac Rescue Helicopter for comment.