"We're a challenger brand and Slingshot's always firmly been in the value proposition of the market so we're well aware that we're going to have to give customers an incentive to move.
"So while we'll deliver on the experience side from a service perspective, we'll absolutely be making sure that customers are saving money as part of the bundle."
Vocus has taken on 25 staff from Switch and Callander said its call centre staff were being trained to take power and broadband-related calls.
The company would remain a telco at its core and there were no plans to sell energy on a standalone basis.
Nonetheless, Callander said they aimed to offer vigorous competition for the big power companies, as well as their traditional telecommunication rivals.
While selling energy would be new to Vocus staff in New Zealand, its Australian parent company had been offering power bundles for some time, "so we're not going in blind", Callander said.
Currently, Trustpower is the only other company which offers broadband and energy packages in New Zealand.
Business and technology commentator Paul Spain said Vocus' bundles could put pressure on other telcos to offer more sweeteners.
"They're buying what I would say is quite a niche player in the power space - they have a much bigger retail presence than the company they're acquiring so they'll be able to leverage that presence to really add value to the acquisition.
"It also puts them in a position to be able to compete a little bit more strongly against some of the other players because really at the moment we've only got Trustpower," Spain said.
"You've got to have some pretty good offering you can drop into the market that makes you stand out."