"Early indications are is that the alert transmitted to all parts of the country with cellphone coverage, which is fantastic," she told Newstalk ZB.
The ministry predicts about half of Kiwis received the alert and said people should go on to the ministry website and fill out a survey about the system.
"We encourage people to fill out the survey on our website to tell us about their experience so we can continue to strengthen the system," Stuart-Black said.
"This is new technology so each time we use it, whether it's in a test like this or it's used in a real situation, it's really important we understand how it's coming across to those who receive it.
"We experience emergencies frequently in New Zealand, so it is a channel we will be using in addition to radio, TV, online and social media to get across critical, lifesaving information."
Last year's test flopped when Vodafone customers received test alerts between 1.30am and 2am on October 4.
Many took to social media to vent about having their sleep interrupted multiple times by repeated texts.
Vodafone huffed in a statement to media: "It is important to clarify the ministry takes full responsibility for sending this error text.
"It was accidentally initiated by one of the ministry's overseas technology suppliers, and not Vodafone or any of the other ISPs involved in the project."
Civil Defence communications manager Anthony Frith told the Herald this morning there's "no chance" of that happening again.
"That was when the system was still in the hands of the Dutch provider [one2many] that created it," Frith says.
Civil Defence now has direct control of alerts, Frith says. He points out that a test in November last year went smoothly.
Strictly speaking, Emergency Mobile Alerts are not txt messages. They use their own dedicated bandwidth, so they are not affected by any congestion on Spark, Vodafone or 2degrees' networks.
Visit the Civil Defence website to provide feedback on the alert and if you didn't receive it, check if your phone is compatible here.
