Moutter said there are more gains to be made migrating customers to fibre, and that his rivals were paying too much to acquire new connections in what's largely a saturated market.
"It is something that frustrates us, the degree of competition driven by acquisition, which is just driving market churn," Moutter said. "That is the state of the market today and we have to play in it and over time I guess it will become a bit more orderly."
Spark is rethinking its wider strategy, and Moutter plans to put it to investors by the middle of the year.
The company is keen to shift its customers from the copper lines owned by Chorus, which have regulated wholesale prices. Of its 675,000 broadband connections, 138,000 are on fibre and more than 40,000 are on Spark's wireless broadband.
Spark has previously signalled it wants to cut its reliance on Chorus's copper lines, and beefed up its call centre service capability after harsh winter conditions caused an increased number of faults last year. It also wants to have more control over fibre assets in central business districts, and this month kicked off a takeover bid for Wellington-based TeamTalk which owns the CityLink fibre business and Farmside rural internet service provider.