But with Flanagan determined not to relinquish the lead over the last lap, Oliver had to settle for second in 9:10.67 while O'Donnell chased down Buscomb for third in 9:14.99.
The NZ junior women's relay squad led some top sprinting action with a national under 20 record, recording 45.04, smashing the previous record of 45.57 which had stood for 22 years.
In the individual sprint events Joseph Miller and Rochelle Coster were clear winners in the 100m A races, winning impressively in 10.36 (+1.5) and 11.41 (+4.2).
Kodi Harman 10.55 and James Mortimer 10.61 filled the minor men's placings while Australian Christine Wearne 11.74 and Lucy Sheat 11.81 came in next in the women's race.
Mortimer turned the tables on Millar and Harman in the 200m winning in a personal best 21.02 with a legal wind.
Coster's 100m win was over some excellent junior talent and she followed it up with a stunning performance over 100m hurdles, stopping the clock at 13.19.
Andrew Whyte ran an impressive 400m in 47.54, winning from Frazer Wickes and Tama Toki, who had earlier won the 400m hurdles while Louise Jones took out the women's 400m narrowly from Brooke Cull.
Michael Dawson and Katherine Marshall were winners over 800m, running impressive times in the gusty conditions.
High Jumper Liz Lamb cleared 1.81 to win the women's high jump and went very close twice at 1.86, a height which would have given her a meeting record. The men's high jump was won by Sam Pinson at 2.02.
Matthew Wyatt jumped a solid 7.45m and Anna Thomson was the winner of the women's triple jump.
Marshall Hall was the standout discus thrower, sending the disc out to 58.01 while Lauren Bruce tossed a handy 56.19m in the hammer.
The top shot putter on the day was junior Ryan Ballantyne with a personal best 17.16 for a clear win.
Results
Women
100m: 1 Coster, Rochelle Paku 11.41. 2 Wearne, Christine Aust 11.74. 3 Sheat, Lucy Marl 11.81.
400m: 1 Jones, Louise Paku 54.81. 2 Cull, Brooke Taka 54.84. 3 Hubbard, Kendra Australia 55.50.
800m: 1 Marshall, Katherine TeAw 2:06.85. 2 Andrews-Paul, Alison Wair 2:09.39. 3 Demeo, Heidi Aust 2:11.49.
3000m NZ Champs: 1 Flanagan, Rosa Cant 9:09.33. 2 Oliver, Lucy NHB 9:10.67. 3 O'Donnell, Lydia NHB 9:14.99.
100m hurdles: 1 Coster, Rochelle Paku 13.19. 2 Morrison, Fiona CHOB 13.55. 3 Torr, Veronica NHBC 13.74.
4x100m Relay: 1 NZ Under 20 'A' 45.04, NZ U20 record. 2 NZ Under 20 'B' 46.60. 3 Lower Hutt 'A' 50.83.
High Jump: 1 Lamb, Elizabeth Wait 1.81m. 2 Skelton, Imogen WHAC 1.66m. 3 Edwards, Phoebe WHAC 1.66m.
Triple Jump: 1 Thomson, Anna Mana 11.92m. 2 Bennett, Ashleigh Hawe 11.22m. 3 Mabonga, Atipa Otau 10.84m.
Shot Put: 1 Fia, Palu PNth 11.59m. 2 Ryan, Emma StPl 10.69m.
Discus: 1 Hakeai, Dina ACA 55.81m. 2 Keenan, Te Rina Wait 53.63m. 3 Vegas, Kasandra Int 42.38m.
Hammer: 1 Bruce, Lauren SCan, 56.19m. 2 Wharehinga, Montaya LowH 49.26m. 3 Mackie, Althea Nth Harbour Bays 38.40m.
Javelin: 1 Leggett-Hilmarsdotti, Melkorka LCty 37.36m. 2 Bonne, Caitlin PTH 36.74m. 3 Davies, Danica Taie 33.81m.
Men
100m: 1 Millar, Joseph Taur 10.36. 2 Harman, Kodi, Taur 10.55. 3 Mortimer, James NHB 10.61.
200m: 1 Mortimer, James NHB21.02. 2 Millar, Joseph Taur 21.04. 3 Harman, Kodi Taur 21.45.
400m: 1 Whyte, Andrew HCty 47.54. 2 Wickes, Frazer NHB, 47.89. 3 Toki, Tama ACA 48.06.
800m: 1 Dawson, Michael Wesl 1:52.54. 2 Hintz, Daniel Taur 1:54.20. 3 Ewing, Harry HamC 1:55.31.
300m: NZ Champs 1 Willis, Nicholas Well 8:00.09. 2 Carson, Hamish Well 8:05.97. 3 Matthews, Julian Tasm 8:07.40.
110m hurdles: 1 Henry, Jack CHOB 14.44. 2 Sandilands, James CHOB 14.94. 3 McDonald, Felix Taie 15.07.
400m hurdles: 1 Toki, Tama ACA 53.83. 2 Wu, Campbell ACA 55.06. 3 Hartley, Quin PNth 56.46.
4x100m: 1 NZ Under 20 'A' 42.08. 2 NZ Under 20 'B' 42.27. 3 Palmerston North 'A' 44.13.
High Jump 1 Pinson, Sam WHAC 2.02m. 2 Peters, Matthew PNth 1.90m. 3 Swan, William Inve 1.85m.
Long Jump: 1 Wyatt, Matthew NHB 7.45m. 2 Peters, Jordan PNth 7.00m, 3 Henry, Jack Chch Old Boys 6.74m.
Shot Put: 1 Ballantyne, Ryan HamC 17.16m. 2 Power, Ben Kiwi 15.76m. 3 Parkinson, Alexander NHB 4.85m.
Discus: 1 Hall, Marshall Inve 58.01m. 2 Parkinson, Alexander NHB 52.83m. 3 Sulupo, Nathaniel LowH 49.30m.
Hammer: 1 Joycey, James Aust 54.35m. 2 Palmer, Nick HastC 46.87m. 3 Whiteman, Nathan Wair 35.75m.
Javelin: 1 Smith, Aidan PNth 55.99m. 2 Te Whata, Taine Wint, 39.22m. 3 Mander, Alex PTH 34.57m.
Mixed
3000m Race Walk: 1 McElwee, Michael Paku 16:34.64. 2 Lake, Sean Scot 16:40.81. 3 Hoskin, Sue, Mana 18:38.19.
Pole Vault: 1 Mander, Alex PTH 3.60m. 2 Maslin, Tom Phoe 3.30m. 3 Richards, Louise Phoe 3.00m.