The championships have attracted 19 boys teams and 18 girls teams from around the country, who qualified through regional tournaments.
Otago won its first game 61-42 against Mid-South Canterbury in the girls competition, while its boys lost 116-51 against Hawke's Bay in their opener.
The boys had a 94-74 loss in their second game against Tasman, while the girls lost 77-73 to Waitakere West.
The tournament runs until Saturday.