There were several rescue vessels out on the water near Motiti Island and the search teams located all three divers by 2pm, he said.
Mr Madden said the exercise was aimed at testing inter-group co-ordination both at a management level and in using search assets.
"We got some learnings out of today's exercise but that is what an exercise is about, identifying areas of improvement and learning from them," he said.
"The exercise is very timely as it is the start of our summer when there is a remarkable increase in the amount of water-based activities, which inherently means more incidents requiring search and rescue."
Mr Madden said if the public took some simple precautions it reduced the chances of getting into trouble.
"Telling someone where you are going and when to expect you back means if you do get into trouble we can get to you quicker. Skippers are also reminded to check the marine weather forecast before you leave home and make sure you have lifejackets for everyone on board," he said.
Mr Madden said he wanted to thank all the volunteers who gave their time today for the better good of the local marine search and rescue response.