Cunningham would convert another penalty in the 25th minute after Whaka were caught offside at the ruck to give the visitors the lead for the only time in the match.
It was the work in the tight which would lay the groundwork for the win for the home side.
Whaka's forwards would have been confident they had the wood over their Rotoiti counterparts going into the game. But the return of Corey Marsters and Justin Nepia to the front row gave the visitors added steel.
However, a lack of game time eventually told on Rotoiti and the constant onslaught from Whaka lead to the first of their five tries.
It was a well-worked pushover try when Whaka decimated Rotoiti's scrum 5m from their line after Joshua White had been sent to the sinbin for deliberately trying to collapse a previous scrum. Hulking No8 Pomare Pirini arose from the tangle of arms and legs triumphant with the ball. Perham converted but it was the last time the kicker managed to thread the ball between the uprights, a real concern with seven of the nine attempts at goal missed.
Whaka scored another try on the stroke of halftime when centre Chris Miller broke a one-on-one tackle to race under the posts to make it 15-6.
The second half was a one-sided affair with Whaka keeping Rotoiti scoreless, and the red and black forward pack going about their job in a ruthless manner.
Darrell Pereira would score Whaka's second try with Dougie Edwards and Perham grabbing the last two.
Whaka coach Maurice Stone said overall he was happy with the way the team performed and not too concerned with the amount of missed kicks.
"Every kicker has an off day. You're going to get that every now and then. Overall the team put in an honest effort and that's all you can ask."
Rotoiti captain Jesse Acton said there was plenty to work on for his team but was confident they could improve.
In the other matches in the premier division Te Puna beat Mt Maunganui 15-14, Te Puke Sports - last year's premier champions - were too strong for Paroa, beating the Eastern Bay side 24-18.
Tauranga Sports beat Greerton Marist 25-18 and Opotiki demolished Rangataua 30-10.
Scorers: Whakarewarewa 30 (Pomare Pirini, Chris Miller, Darrell Pereira, Douglas Edwards, Chanse Perham tries; Chanse Perham 1 pen, 1 con) Rotoiti 6 (Whakataki Cunningham 2 pens) Halftime: 15-6.