I do remember playing against Robert Ten Broeke in the Junior National Cup, Stop Out v Miramar Rangers.
He got selected to represent New Zealand on September 11th 1978 aged 16 years 341 days, beating David Taylor's record of 17 years 198 days.
For the record New Zealand lost to Iran 2-1.
Don't think he ever played for NZ again.
Ten Broeke never played in an international for NZ , only against club sides.
NZ's games in 1978 (scroll down to 1978):
http://www.rsssf.com/tablesn/nz-intres-det70.html#78
This reliable website of the International Federation of Football Statisticians reveals Ten Broeke only ever played in four games against club sides. (vs. "Paas", "FAR Rabat", "Eintracht Frankfurt u-21", "Selangor FC") in three games in Korea and one in Kuala Lumpur in September 1978.
:Ten Broeke is also recorded here as only playing in non-A internationals and never earned a cap:
"NCE apps" = "Non-Cap Earning appearances":
http://www.ultimatenzsoccer.com/NZRepSoccer/caps_and_goals.htm
Hence I think Ceri Evans would be our youngest full international as in my post above:
Made his A international debut aged 17 years and 14 days in a 5-1 win over Kuwait on October 16 1980 in the Merdeka tournmanet in Malaysia. Started in all seven games for NZ in the tournament. Adshead must have considered him too young for the 1981-82 All Whites - plus he had school work leading in to his first year at university in 1982. http://www.ultimatenzsoccer.com/NZRepSoccer/id1563.htm He made his National League debut aged 15 for Nelson in 1979.