Isaac Misky displayed the Whalers' intentions early in the match, scoring within minutes of the first whistle.
On attack the Whalers looked confident and composed as they dominated the Chargers in their own half.
Misky looked as though he would get a second try as he broke the defensive line, chipped over the fullback and regathered, only to be caught metres out, but the Whalers continued to press.
The backs did their job effectively as Kail Spooner scored a try with the defence stretched.
Man of the match Sam Brame sucked in defenders and gave opportunities to the backs to score, also proving a nuisance in defence.
Although the Chargers were tenacious and hard-hitting in defence, they came off second best.
Hyrum Martin showed his worth as he fended his way through the Chargers, beating three defenders to score an impressive try.
The Whalers' resilient defence cracked as Jade Coleman scored for the Chargers.
The final try of the half went to Louis Tili after the pressure proved too much for them, leaving the score at 22-6 for the half.
The Chargers looked eager to drag their way back into the game, but their hope was dashed as Jalan Wallace dotted down in the right-hand corner for Otago.
Hyrum Martin obliterated their hopes after fending off five defenders to score his second try of the match. There were some massive hits as the Chargers' frustrations came to the fore.
Otago shrugged off the confrontation as Dexter Buchanan scored under the posts after Ben McKerchar broke the line, drawing in the fullback.
Misky crossed over for his second and the Whalers' final try of the match, walking over the tryline uncontested.
Otago tired towards the end of the match. The Chargers, with 20 minutes to go, found themselves in Otago's half and managed to stretch the defence as Ben Waipouri dotted down. Damien Wineera had an impact off the bench as he followed up with two more tries for his side.
The Tasman Titans lost 28-24 to Canterbury Development, while Southland had the bye.
By Thomas Heaton.
South Island league
The scores
Whalers 44
Isaac Misky 2, Hyrum Martin 2, Jalan Wallace, Kail Spooner, Louis Tili, Dexter Buchanan tries; Ben McKerchar 6 goals
Chargers 20
Damien Wineera 2, Jade Coleman, Ben Waipouri tries; Deane Coghlan 2 goals
Halftime: 22-6
