Under 11 grade Small Blacks rugby will change from 15-a-side on a full-field, to 10-a-side on a half field next season.

New Zealand Rugby is making a number of changes for 2020 including a new new club rugby and secondary school initiative known as 'Game On'

It's designed to reduce the number of default matches due to lack of flexibility for player numbers.

There will be rolling substitutions and teams will be able to modify team size, game length and scrum contests.