He said it was "inevitable" there would be changes to Civil Defence's structure after the problems.
"We want to get through this current circumstance ... there'll be all sorts of suggestions about changes, and some of those will ultimately be reflected in the law.
"The whole command and control structure of [MCDEM] needs to be looked at."
Brownlee would discuss possible legislative changes with political parties in two weeks, Fairfax reported.
A national, cellphone-based early warning system for natural disasters was also on its way.
"There are protocols that have to be worked through with the telcos, they have been very cooperative in discussions to date ... the last set of discussions that I had would have indicated it [the system] was a couple of months away," Brownlee said.
The announcement was welcomed tonight by WeatherWatch, which said it had voiced concern about earlier failures relating to the country's tsunami warning system.
"We were losing faith in their ability to communicate fast and effectively to the public.
"This week yet again there were more failures - the kind that can cost lives if people are not warned in time of a potential disaster.
"We're pleased this long-overdue overhaul is going to be taking place - we live in a country that is highly vulnerable to natural disasters and they can occur at midnight in bed or lunchtime at work. An overhaul and rethink in this area will only serve the nation well and help better protect each and every one of us living here."