Swimming New Zealand manager Philip Rush said the festival was an important development opportunity for the sport.
"All but four Australian Youth Olympic Festival records were broken in the pool which points to the level of competition this week," Rush said.
"We are a small nation with only a few quality swimmers but we need to develop a larger base. This competition has allowed that.
"Our swimmers need to train and race harder but in saying that around 80 per cent of swims were personal bests and a positive sign was that swimmers, in the main, bettered their morning times in the evening finals.
"This shows that the programmes are working in this regard. We need to be able to swim fast in the morning and faster in the evening which is what we need to do to be able to compete on the international swimming stage."
Day 4 New Zealand results:
800m freestyle: Grace Sommerville (Ashburton) 9:05.88, 5; Monique King (North Shore) 9:08.10, 8.
200m individual medley: Ryo Fujimoto (JPN) 2:03.29, 1; Evan White (CAN) 2:04.30, 2; Bradley Ashby (Hamilton) 2:04.37, 3.
200m breaststroke: Jenna Strauch (AUS) 2:37.55, 1; Sydney Pickrem (CAN) 2:31.09, 2; Natasha Lloyd (North Canterbury) 2:31.36, 3. Abbie Johnston (Aquagym) 2:37.46, 8.
200m breaststroke: Ben Walsh (Porirua Aquatics) 2:25.02, 7.
1500m freestyle: Carter Edgecombe (Fairfield) 16:04.36, 7.
Women 400m medley relay: NZL 4:18.18, 6.
Men 400m medley relay: NZL 3:55.29, 6.