Two bodies have been found in a stream in Waitakere near where three people were swept away by water near Cascade Falls.
Police said a group of five people were trying to cross the waterway when they got into trouble.
One person has been rescued and transported to Waitakere Hospital in a moderate condition.
The other man who had earlier made it to safety was also taken to hospital with minor injuries.
The fifth person involved was uninjured.
Police are checking whether the bodies located are part of this group.
Police have set up a command centre at the Waitakere Golf Club.
RNZ's reporter at the centre said the foot bridge to Cascade Falls had collapsed, which hampered the search for the missing people.
A Westpac Rescue Helicopter has been circling the area, and St John Ambulance, police and search and rescue are all at the scene.