Auckland Emergency Management Group say some parts of the region received more than a month's worth of rain in one day - with up to 120mm being recorded in some places.
Council teams are responding to around 30 critical requests for service relating to downed trees, and more than 400 relating to flooding on public land.
There have also been a couple of requests from people being displaced.
Aucklanders are being told to use the council's Report a Problem online tool or via the contact centre for drains and trees on public land - or contact insurers for private property.
Emergency management will stand down at 6pm and monitor the situation overnight.
