Wiegersma (22), who will compete in the 200m and 400m individual medley events in London, will not be contesting her Olympic events.
However, she will be honing her individual skills when she competes in the open women's 50m breaststroke, 100m backstroke, 200m freestyle and 200m butterfly, for the Waverley club.
Wiegersma made her international debut in 2006, when she won a gold medal in the 100m backstroke at the World Youth championships in Rio de Janeiro.
Her best international performance in senior ranks was at the Commonwealth Games in Delhi, in 2010, when she finished fourth in the 200m IM.
The big test for Wiegersma will come in the 100m backstroke, where she is pitted against Otago specialist Kate Godfrey (Neptune).
The last time the pair met was at the New Zealand championships in Auckland, when Wiegersma won the 400m individual medley in 4min 41.74sec to qualify for the Olympics.
Godfrey stood on the podium for the first time at an open championships when she won the silver medal.
A close contest is likely, as Wiegersma has a best short-course time of 1min 00.89sec and Godfrey 1min 02.89sec.
Wiegersma will have an easier task in the 200m butterfly, as her time of 2min 10.95sec gives her an 8sec cushion over Caitlin Rennell, of the Jasi Club, of Christchurch.
Godfrey is the favourite to win the women's open 200m backstroke. Her short-course time of 2min 12.70sec is 7sec faster that Chelsea Easter (Wharenui).
Neptune's Katie Kenneally will need to be in her best form to win the women's 100m individual medley from Nicky Pio (Wharenui) and Godfrey.
Kenneally will be tested by the promising Natasha Lloyd (North Canterbury) and Abbie Johnston (Aquagym) in the women's 100m breaststroke.
A strong group of swimmers is coming from Canterbury for the meet.
Starting times for the five sessions: today (6.15pm start), Saturday, (8.30am and 4pm), Sunday (8.30am and 2 pm).
