Hopkins (14) has made rapid progress since joining Gennadiy Labara's Osca training squad.
Hopkins was Otago's best swimmer at last year's age-group championships in Wellington, winning nine medals - seven gold and two silver - and breaking six Otago records.
He has the top ranking in six events in the boys aged 14 grade and has second ranking in the 100m butterfly. His top-ranking swims are in the 200m individual medley (2min 15.26sec), 50m butterfly (28.33sec), 200m freestyle (2min 1.34sec), 50m freestyle (25.67sec), 400m individual medley (4min 49.74sec) and 100m freestyle (55.71sec).
The other member of the Osca squad tipped to do well is Andrew Trembath (Neptune), who was Otago's best performer at the South Island short-course championships last year. He broke seven Otago aged 14 and 15 records and eight South Island records.
Trembath joined the Osca squad when his family shifted to Dunedin after the Christchurch earthquake. He is ranked second in the 200m individual medley (2min 9.37sec) and 400m medley (4min 36.80sec) and is ranked third in the 50m and 100m breaststroke.
Aleisha Ruske (Neptune), who won a gold, silver and bronze at last year's championships, is ranked first in the girls aged 15 200m butterfly (2min 23.98sec) and second in the 100m freestyle (59.73sec).
Hang Zhang (Neptune), a promising member of the Osca squad, is ranked top in the boys aged 15 100m breaststroke (1min 08.75sec) and second in the 200m breaststroke (2min 28.66sec).
Caitlin Deans (Waves) is ranked second in the girls aged 12 and 13 400m freestyle (4min 38.35sec) and the 800m freestyle (9min 44.17sec).
Oamaru swimmers Isobel Ryan and Jeremy Tasker made significant progress with their performances at the Otago and Canterbury championships at Moana Pool last month.
Ryan, a pupil at St Kevin's College, is competing in the girls aged 16 backstroke and freestyle events, and Tasker in the men's aged 18 grade. Tasker left Waitaki Boys' High School last year and is studying marketing and commerce at the University of Otago.
Other Otago swimmers likely to reach the podium include Sophie Gibson (Queenstown), Sophie Fairbairn (Wanaka), Thomas Heaton (Waves) and Stef Gillespie (Zenith).
The championships, at the Wellington Regional Aquatics Centre, start today and finish on Saturday.