Family and friend's of all three were at the service and shared memories, as well as photos with the crowd in the gym at Burnham Military Camp.
Today's service comes just a fortnight after a military commemoration service for two other Burnham-based soldiers, Lance Corporals Pralli Durrer and Rory Malone, both 26.
Sir Mateparae spoke of all three being the "brave children of Tumatauenga - the god of war''.
"Warfare has taken your lives, but you lay here in great honour,'' he said.
"At times like this, with 10 New Zealand soldiers having lost their lives in Afghanistan - five in a matter of weeks - it is natural that we question why we are there. In a democracy, it is right that we can and should ask questions.
"The three young soldiers we mourn today knew well the risks of service in Afghanistan. It is a place where safety can never be guaranteed, and it has a tortured history of conflict that stretches back many centuries,'' he said.
Mr Key said Burnham had endured a succession of blows and said although defence personal were seen as tough people, even tough people could weep.
Major Craig Wilson, who was injured in the earlier attack in Bamiyan earlier this month, also spoke to the crowd, often holding back tears.
He was the commanding officer of all five soldiers who were killed in Afghanistan this month.
