Auckland mayor Wayne Brown has vowed agencies will be better prepared for the possible deluge today than last week's unprecedented rainfall.
He has defended himself against criticism over the lack of communication and the time taken to declare a state of emergency on Friday for the city, which witnessed record rainfall in the flooding that claimed three lives.
A red rain warning is in place for north of Orewa and an orange warning begins at 8pm on Tuesday for the rest of Auckland, including Great Barrier Island.
In an interview with RNZ on Tuesday afternoon, Brown said he was certain they were ready for the possible deluge on Tuesday night and would be better prepared than last Friday.
"I am absolutely sure it will be better and we will continue to improve. The level of communications will be something of course which is subject to review later on, but I am absolutely sure they are improved from what they were last Friday.
"We have learned lessons. And we are listening."
It was revealed today a producer for MediaWorks news station Today FM on Saturday said Brown turned down an interview on Friday morning because he wanted to play tennis instead.
WhatsApp messages leaked to the New Zealand Herald showed rain got in the way, with Brown telling friends on Saturday morning it was "pissing down so no tennis". Despite being freed up, the interview did not go ahead.
And on Saturday night, Brown told the WhatsApp group - known as 'The Grumpy Old Men' - he could not play on Sunday either because "I've got to deal with media drongos over the flooding".
In a statement from his office later, a spokesperson said: "The mayor was having a private conversation. His priority at this time is the ongoing emergency response and keeping Aucklanders safe with the region being lashed by severe weather."
In his interview with RNZ, Brown reiterated the need for a review of the city's actions and preparedness for coping with last Friday's extreme weather - including his own actions.
But he said the flooding across the city was like 27 floods spread across the region.
"This is unprecedented. I don't think anyone really was fully prepared for anything like this. I am going to commission a review to look into everything; how prepared were our emergency services for this.
"There have been some shortcomings. There are lots of things we could have done better.
"We will look at everything, from my actions and my offices actions down to all the emergency groups. No-one will escape from this. We want to prepare better for the future."
Support was being organised to deal with flood debris and rubbish and an Auckland Emergency Relief Fund was available to help with financial problems.
"This is a fund set up to help families, individuals, and community organisations who have suffered financial hardship from this flood [...] I acknowledge the many organisations setting up to contribute, and I encourage citizens and organisation who haven't been damaged by this to contribute," he said.
Auckland Emergency Management urged people to act fast if they saw rising water - evacuate to higher ground and do not wait for official warnings.
"Stay home. Stay safe. Look after your neighbours," Brown said.
Auckland City Council says if life is in danger, call 111 immediately.