Shanks said she was delighted with the performance, which shows she and her team's pursuit teammates are on target leading in to next week's World Cup in Colombia and on to next year's Olympics.
"We are not peaking by any means. This shows we have good early-season form and gives us real confidence looking ahead," Shanks said. "I've spent more time on the road and more time in the gym in the build-up and it shows we are well on track.
"It's just the second time I have been under 3:30. I have had so many rides in the 3.30s so this is a big breakthrough tonight."
Sergent said he was focused on a top performance in what could be his final individual pursuit, as he moves his focus to the road after the team's pursuit campaign to the London Olympics.
"I felt quite tired after the morning ride but had a good recovery and a sleep in the afternoon and felt really refreshed," Sergent said. "I wanted to get that record for sure and I wanted to take advantage with the track running fast.
"Overall I am really encouraged by things. That 3:55 with the team's pursuit yesterday has not really sunk in and tonight was also really pleasing. We have had a very limited track build up to this so, overall, I think we are in excellent shape."
The records also fell in the under-19 ranks when Waimate's Dylan Kennett took out the 1000m time trial. Kennett, who set a national record in winning the individual pursuit yesterday, clocked 1:03.644 to claim the kilo time trial, which broke Eddie Dawkins' 2007 ride of 1:03.700.
Auckland's Georgina Wilson, eighth at the world championships in Moscow this year, took out the women's under-19 final, clocking 2:30.257, a new personal best.
Outstanding Southland-based sprinter Natasha Hansen made it three from three when she came from the rear of the field to dominate the final of the women's keirin after winning the team's sprint and the 500m time trial.
She is looking to recover before chasing a national record in the individual sprint on Thursday.
The fans were treated to a star of the future in world junior champion Caleb Ewan from Australia who won the under-19 omnium, winning four of the six events including all three last night _ the individual pursuit, scratch race and time trial. He finished clear of Nelson's Kristoff Ford.
Te Awamutu's Hayden McCormick rounded out the evening with a brilliant performance, the only rider to lap the field in winning the under-19 points race over 20kms.
