"The biggest reward for me is seeing players kick on and go on to not only be better rugby players but also better fathers and better people. Rugby can be the vehicle for that," said Ngarimu, who won the backing of Poverty Bay again this year, despite the team finishing second last, just a win above East Coast.
Matthews takes up his first campaign with the national team.
The New Zealand Heartland XV squad, due to be selected from Mitre 10 Heartland Championship sides at the end of the 2016 season, will play New Zealand Marist and the Australian Barbarians.
"I love coaching at all levels of the game but Heartland rugby is very special," said Matthews. "The standard of Heartland rugby goes from strength to strength every year and more and more players are being picked up for Mitre 10 Cup and Investec Super Rugby. It shows how much talent we have in New Zealand."
Tony Harrison, who manages Mid-Canterbury, is the Heartland XV manager.
"It's the goal of many Heartland players to make the New Zealand Heartland XV team. I'm thrilled to be involved," said Matthews.
The Heartland XV play NZ Marist for the McCrea Cup annually. The Aussie Baabaas will be selected from non-Super Rugby contracted players playing in the National Rugby Championship. Tour dates and locations are to be confirmed for November.